Showing papers on "Microstrip published in 2013"
Book•
11 Jan 2013
TL;DR: Waterhouse et al. as mentioned in this paper proposed an approach to improve the performance of single-layer patch antennas by reducing the size of the patch array and increasing the bandwidth of the antenna array.
Abstract: Acknowledgements. 1: Introduction R. Waterhouse. 1.1. History. 1.2. Advantages and Issues. 1.3. Applications. 1.4. Summary of Book. 1.5. Bibliography. 2: Fundamental Properties of Single Layer Microstrip Patch Antennas R. Waterhouse, D. Novak, D.-K. Park, Y. Qian, T. Itoh. 2.1. Introduction. 2.2. General Theory of Operation and Design Tools. 2.3. The Effect of Conductor Shape. 2.4. Impedance and Radiation Performance of Single Layer Patches. 2.5. Excitation Methods of Microstrip Patches. 2.6. Circular Polarization Generation. 2.7. Summary. 2.8. Bibliography. 3: Enhancing the Bandwidth of Microstrip Patch Antennas R. Waterhouse, J.T. Aberle, D. M. Kokotoff, A. Mitchell, M. Lech, S.D. Targonski, M. Lye, F. Zavosh, K. Ghorbani, D. Novak, A. Nirmalathas, C. Lim. 3.1. Introduction. 3.2. Intuitive Procedures. 3.3. Horizontally Coupled Parasitic Patches. 3.4. Stacked Patches. 3.5. Large Slot Excited Patches. 3.6. Aperture Stacked Patches. 3.7. Ultra-wideband ASPs. 3.8. Summary. 3.9. Bibliography. 4: Improving the Efficiency of Microstrip Patch Antennas R. Waterhouse, D. Pavlickovski, D. M. Kokotoff, J.T. Aberle. 4.1. Introduction. 4.2. Surface Waves. 4.3. Patches that do not Excite TM Surface Waves. 4.4. Hi-lo Stacked Patches. 4.5. Photonic Band-gap Structures. 4.6. Summary. 4.7. Bibliography. 5: Small Microstrip Patch Antennas R. Waterhouse, H.K. Kan, D.M. Kokotoff, S.D. Targonski, J.T. Rowley, D. Pavlickovski. 5.1. Introduction. 5.2. Shorted Microstrip Patches. 5.3. Further Size Reduction Techniques for Shorted Patches. 5.4. Winged Shorted Patch. 5.5. Shorted Spiral Patches. 5.6. Improving the Performances of Shorted Microstrip Patches. 5.7. Performance of Shorted Microstrip Patch Antennas for Mobile Communications Handsets at 1800 MHz. 5.8. Summary. 5.9. Bibliography. 6: Direct Integration of Microstrip Antennas R. Waterhouse, W.S.T. Rowe, D. Novak, A. Nirmalathas, C. Lim. 6.1. Overview for Requirernents for Integration. 6.2. Slot Coupled Procedures and Solutions. 6.3. Direct Contact Procedures and Solutions. 6.4. Summary. 6.5. Bibliography. 7: Microstrip Patch Arrays R. Waterhouse, K. Ghorbani, W.S.T. Rowe, S.D. Targonski, L. Mali, H.K. Kan, D. Novak, A. Nirmalathas, C. Lim. 7.1. Introduction. 7.2. Series Fed Arrays. 7.3. Parallel Fed Arrays. 7.4. Combination Fed Arrays. 7.5. Large Scanned Arrays of Microstrip Patches. 7.6. Alternatives to Large Arrays of Microstrip Patches. 7.7. Wraparound Patch Antenna Arrays. 7.8. Summary. 7.9. Bibliography. 8: Summary R. Waterhouse. 8.1. Overview. 8.2. Future Directions of Microstrip Patch Technology. 8.3. Bibliography. List of Contributors.
220 citations
TL;DR: In this article, a slotted meander-line resonator (SMLR) is used to block the surface current at the resonant frequency of two patch antennas coupled along H-plane and operating at a frequency of 4.8 GHz.
Abstract: A new approach to enhance the isolation in microstrip patch antenna arrays is described in this letter. The implementation of a slotted meander-line resonator (SMLR) is done by creating defect in the microstrip structure particularly designed for band-notch function. The resonator is designed to block the surface current at the resonant frequency of the two patch antennas coupled along H-plane and operating at a frequency of 4.8 GHz. The interelement isolation before and after the implementation of SMLR has been investigated. The proposed configuration provides an improvement in isolation by 16 dB (measured value) with a reduced edge-to-edge spacing of 7 mm $(\lambda_{o}/9)$ . The configuration has been designed, simulated, and validated experimentally.
195 citations
Patent•
4 Apr 2013TL;DR: In this paper, a circuit assembly with a package substrate (304-A) and an integrated circuit (IC) (302-A), where the IC is secured to the package substrate and is electrically coupled to the microstrip line.
Abstract: An apparatus is provided. There is a circuit assembly (206-A1) with a package substrate (304-A) and an integrated circuit (IC) (302-A). The package substrate has a microstrip line (208-A1), and the IC is secured to the package substrate and is electrically coupled to the microstrip line. A circuit board (202-A) is also secured to the package substrate. A dielectric waveguide (204- A) is secured to the circuit board. The dielectric waveguide has a dielectric core (310-A) that extends into a transition region (314- A) located between the dielectric waveguide and the microstrip line, and the microstrip line is configured to form a communication link with the dielectric waveguide.
165 citations
TL;DR: In this article, a three-dimensional (3-D) bandpass frequency-selective structures (FSSs) with multiple transmission zeros is presented to realize wide out-of-band rejection.
Abstract: A new class of three-dimensional (3-D) bandpass frequency-selective structures (FSSs) with multiple transmission zeros is presented to realize wide out-of-band rejection. The proposed FSSs are based on a two-dimensional (2-D) array of shielded microstrip lines with shorting via to ground, where two different resonators in the substrate are constructed based on the excited substrate mode. Furthermore, metallic plates of rectangular shape and “T-type” are inserted in the air region of shielded microstrip lines, which can introduce additional resonators provided by the air mode. Using this arrangement, a passband with two transmission poles can be obtained. Moreover, multiple transmission zeros outside the passband are produced for improving the out-of-band rejection. The operating principles of these FSSs are explained with the aid of equivalent circuit models. Two examples are designed, fabricated, and measured to verify the proposed structures and circuit models. Measured results demonstrate that the FSSs exhibit high out-of-band rejection and stable filtering response under a large variation of the incidence angle.
145 citations
TL;DR: In this article, an open stub-loaded shorted stepped-impedance resonator (OSLSSIR) with two identical open stubs loaded at its impedance junctions is proposed.
Abstract: This paper presents a new class of dual-, tri- and quad-band BPF by using proposed open stub-loaded shorted stepped-impedance resonator (OSLSSIR). The OSLSSIR consists of a two-end-shorted three-section stepped-impedance resistor (SIR) with two identical open stubs loaded at its impedance junctions. Two 50- Ω tapped lines are directly connected to two shorted sections of the SIR to serve as I/O ports. As the electrical lengths of two identical open stubs increase, many more transmission poles (TPs) and transmission zeros (TZs) can be shifted or excited within the interested frequency range. The TZs introduced by open stubs divide the TPs into multiple groups, which can be applied to design a multiple-band bandpass filter (BPF). In order to increase many more design freedoms for tuning filter performance, a high-impedance open stub and the narrow/broad side coupling are introduced as perturbations in all filters design, which can tune the even- and odd-mode TPs separately. In addition, two branches of I/O coupling and open stub-loaded shorted microstrip line are employed in tri- and quad-band BPF design. As examples, two dual-wideband BPFs, one tri-band BPF, and one quad-band BPF have been successfully developed. The fabricated four BPFs have merits of compact sizes, low insertion losses, and high band-to-band isolations. The measured results are in good agreement with the full-wave simulated results.
144 citations
Patent•
25 Apr 2013
TL;DR: In this article, an IC package comprising a substrate having a first metal layer, a second metal layer and a dielectric layer disposed between the first and second metal layers is described.
Abstract: An apparatus includes an IC package comprising a substrate having a first metal layer, a second metal layer, and a dielectric layer disposed between the first and second metal layers. The IC package further comprises an IC die disposed at a surface of the substrate and comprising RF circuitry. The first metal layer comprises a microstrip feedline extending from a pin of the IC die. The microstrip feedline includes a conductive trace having a probe element at a tip distal from the pin. The first metal layer further comprises a waveguide opening comprising a region surrounding the probe element, the region being substantially devoid of conductive material. The substrate further comprises a plurality of metal vias disposed at the perimeter of the region, the metal vias extending from the first metal layer to the second metal layer.
143 citations
TL;DR: In this article, a printed reconfigurable ultra-wideband (UWB) monopole antenna with triple narrow band-notched characteristics is proposed for cognitive radio applications, which can work at eight modes by controlling switches ON and OFF.
Abstract: A printed reconfigurable ultra-wideband (UWB) monopole antenna with triple narrow band-notched characteristics is proposed for cognitive radio applications in this paper. The triple narrow band-notched frequencies are obtained using a defected microstrip structure (DMS) band stop filter (BSF) embedded in the microstrip feed line and an inverted π-shaped slot etched in the rectangular radiation patch, respectively. Reconfigurable characteristics of the proposed cognitive radio antenna (CRA) are achieved by means of four ideal switches integrated on the DMS-BSF and the inverted π-shaped slot. The proposed UWB CRA can work at eight modes by controlling switches ON and OFF. Moreover, impedance bandwidth, design procedures, and radiation patterns are presented for analysis and explanation of this antenna. The designed antenna operates over the frequency band between 3.1 GHz and 14 GHz (bandwidth of 127.5%), with three notched bands from 4.2 GHz to 6.2 GHz (38.5%), 6.6 GHz to 7.0 GHz (6%), and 12.2 GHz to 14 GHz (13.7%). The antenna is successfully simulated, fabricated, and measured. The results show that it has wide impedance bandwidth, multimodes characteristics, stable gain, and omnidirectional radiation patterns.
140 citations
TL;DR: In this paper, a two-port printed microstrip rectenna with compact structure for communication systems is presented, where the vertical feed port receives the microwave energy and transfers it to the rectifying circuit for dc power generation, while the horizontal feed port is used for data communication.
Abstract: A novel design of a two-port printed microstrip rectenna with compact structure for communication systems is presented An aperture-coupled dual polarization patch antenna is utilized as the receiving antenna The vertical feed port receives the microwave energy and transfers it to the rectifying circuit for dc power generation, while the horizontal feed port is used for data communication, with high isolation between the two ports This patch antenna includes harmonic suppression functionality, which is essential for high microwave—direct current (mw-dc) conversion efficiency A co-simulation procedure using HFSS and ADS for the analysis of the rectenna and the rectifying circuit design is used This design assumes low input power for the rectifying circuit to comply with safety standards A mw-dc conversion efficient of 63% is measured with a 900 $\Omega$ load, 578 GHz operation frequency, and 25 mW receiving power For the communication port, the measured reflection coefficient is $-$ 18 dB at 61 GHz center frequency, the gain is 70 dBi, and the cross polarization in the broadside direction is $-$ 15 dB
138 citations
TL;DR: In this paper, microstrip patch structured rectennas are evaluated and compared with an emphasis on the various methods adopted to obtain a compact rectenna, harmonic rejection functionality, and frequency and polarization selectivity.
Abstract: In the last few years, several antenna designs of rectenna that meet various objectives have been proposed for use in RF energy harvesting. Among various antennas, microstrip patch antennas are widely used because of their low profile, light weight, and planar structure. Conventional patch antennas are rectangular or circular in shape, but variations in their basic design are made for different purposes. This paper begins with an explanation and discussion of different designs, put forward with an aim of miniaturization, harmonic rejection, and reconfigurability. Finally, microstrip patch structured rectennas are evaluated and compared with an emphasis on the various methods adopted to obtain a compact rectenna, harmonic rejection functionality, and frequency and polarization selectivity.
123 citations
TL;DR: In this paper, a Wilkinson power divider on a single-layer microstrip line that can reduce the occupied area, suppress the harmonic components, and/or provide the arbitrary power division ratios is described.
Abstract: This paper describes a new Wilkinson power divider on a single-layer microstrip line that can reduce the occupied area, suppress the harmonic components, and/or provide the arbitrary power division ratios. It consists of two-section transmission lines, two inductors, and one isolation resistor. Four different designs have been conducted to investigate the capabilities of the structure. In addition, a compact divider along with harmonic suppression and a practical divider with a large power-dividing ratio has been constructed and measured. The simulation and measurement results are in good agreement with each other. This indicates that the structure can effectively be used as a power divider for miniaturized or arbitrary power division ratio applications.
122 citations
TL;DR: In this paper, a power divider with high selectivity bandpass behavior is presented and analyzed theoretically, based on the coupled-resonator topology, the circuit area of the proposed power dividers can be reduced as the size of the assembled resonators shrinks.
Abstract: Miniaturized power dividers with high-selectivity bandpass behavior are presented and analyzed theoretically in this paper. Based on the coupled-resonator topology, the circuit area of the proposed power divider can be reduced as the size of the assembled resonators shrinks. Therefore, in order to effectively reduce the circuit area and improve the stopband performance, the net-type resonator is selected to design the filtering power dividers. For demonstration, power dividers with Chebyshev- and quasi-elliptic bandpass responses have been designed and fabricated with microstrip in printed circuit boards. The highly symmetric structure of each power divider provides a low in-band magnitude and phase imbalances. Consequently, the proposed filtering power dividers have advantages of small size, sharp skirt selectivity, high isolation, and superior out-of-band performance. All measured results are in good agreement with the full-wave simulation results.
TL;DR: In this article, a defected ground structure (DGS) was used to control higher order modes up to third harmonic of the fundamental operating frequency in a microstrip line-fed patch antenna.
Abstract: Controlling higher order modes up to third harmonic of the fundamental operating frequency in a microstrip line-fed patch antenna has been successfully demonstrated. Harmonic rejection in the antenna has been achieved at its feed level using highly compact design of defected ground structure (DGS). Rejection characteristics have been improved adding an open stub to the feed line. All possible higher order modes occurring in between the fundamental and the 3rd harmonic have been identified. Relative suppression of radiated fields with and without DGS-control has been quantitatively measured and effective control of harmonics has been experimentally ensured. The area occupied by the proposed DGS has been compared with earlier designs and over 40-90% reduction in size has been documented.
TL;DR: In this article, several new types of low-cost and robust magnetic near-field probes manufactured in low-temperature co-fired ceramics (LTCC) are presented.
Abstract: Several new types of low-cost and robust magnetic near-field probes manufactured in low-temperature co-fired ceramics (LTCC) are presented in this paper. Parallel C-shaped strips and their variations are inserted into the loop area in the front end of probes to achieve common-mode high-pass and notch filters for electric-field noise suppression. These probes with this kind of filter have excellent wideband electric field suppression. They are called high electric field suppression probes type A ~ D. The size of loop aperture in all probes is 100 μm long and 400 μm wide. The signal received from the loop is routed to a measurement apparatus through a semi-rigid coaxial cable with an outer diameter of 0.047 in. The flip-chip junction with low loss and good shielding is used between the probe head in LTCC and the semi-rigid coaxial cable. We take the probes over a 2000-μm-wide microstrip line as device-under-test to measure the probe characteristics. The isolation between electric and magnetic fields for a reference probe based on an old design using the same LTCC process is better than 30 dB from 0.05 to 12.65 GHz. The type A probe has two parallel C-shaped strips, it has better isolation of 35 dB from 0.1 to 11.05 GHz. Type C has one end of its strip shorted to ground, its 30-dB isolation frequency range can be extended to 0.05 ~ 17.8 GHz. With additional layout variation in type D, isolation can be improved to 40 dB up to 10.9 GHz. The spatial resolution for these probes is 140 μm when the distance between the metal surface of the microstrip line and the nearest edge of the loop is held at 120 μm. The calibration factors of the proposed probes are only slightly increased as compared with reference probe.
TL;DR: It is shown that with appropriate phase compensation, the radiation properties of the array can be autonomously recovered as the surface of the flexible array changes shape during normal operation.
Abstract: A phased-array test platform for studying the self-adapting capabilities of conformal antennas is developed and presented. Specifically, a four-port 2.45-GHz receiver with voltage controlled phase shifters and attenuators is designed along with four individual printed microstrip patch antennas attached to a conformal surface. Each antenna is connected to the corresponding receiver port with a flexible SMA cable. It is shown that with appropriate phase compensation, the distorted radiation pattern of the array can be recovered as the surface of the conformal array changes shape. This pattern recovery information is then used to develop a new self-adapting flexible 1 t 4 microstrip antenna array with an embedded flexible sensor system. In particular, a flexible resistive sensor is used to measure the deformation of the substrate of a conformal antenna array, while a sensor circuit is used to measure the changing resistance. The circuit then uses this information to control the individual voltage of the phase shifters of each radiating element in the array. It is shown that with appropriate phase compensation, the radiation properties of the array can be autonomously recovered as the surface of the flexible array changes shape during normal operation. Throughout this work, measurements are shown to agree with analytical solutions and simulations.
TL;DR: In this paper, a novel wide-slot ultrawideband (UWB) antenna with dual band-notched characteristics is presented, which consists of an inverted U-shaped slot on the ground plane and a radiation patch similar to the slot that is fed by a 50-Ω microstrip line.
Abstract: A novel compact wide-slot ultrawideband (UWB) antenna with dual band-notched characteristics is presented. The antenna consists of an inverted U-shaped slot on the ground plane and a radiation patch similar to the slot that is fed by a 50-Ω microstrip line. By etching a C-shaped slot on the radiation patch and extruding an L-shaped stub from the ground plane, dual band-notched properties in the WiMAX (3.4-3.69 GHz) and WLAN (5.15-5.825 GHz) are achieved. The proposed antenna has a compact size of 20×27 mm2 and operates from 2.89 to 11.52 GHz. Furthermore, nearly omnidirectional radiation patterns and constant gain are obtained in the working band.
TL;DR: In this paper, two single fed low profile cavity-backed planar slot antennas for circular polarization (CP) applications are first introduced by half mode substrate integrated waveguide (HMSIW) technique.
Abstract: In this paper, two single fed low-profile cavity-backed planar slot antennas for circular polarization (CP) applications are first introduced by half mode substrate integrated waveguide (HMSIW) technique. One of the structures presents right handed CP (RHCP), while the other one offers left handed CP (LHCP). A single layer of low cost printed circuit board (PCB) is employed for both antennas providing low-cost, lightweight, and also easy integration with planar circuits. An inset microstrip line is used to excite two orthogonal quarter-wave length patch modes with required phase difference for generating CP wave. The new proposed antennas are successfully designed and fabricated. Measured results are in good agreement with those obtained by numerical investigation using HFSS. Results exhibit that both antennas present the advantages of conventional cavity backed antennas including high gain and high front to back ratio (FTBR).
TL;DR: In this paper, a balanced-to-balanced power divider with arbitrary power division was proposed, which can be regarded as the balanced form of a Gysel power dividers.
Abstract: In this paper, a balanced-to-balanced power divider is proposed, for the first time, with arbitrary power division, which can be regarded as the balanced form of a Gysel power divider. The constraint rules are provided for its mixed-mode and single-ended S-parameters. The six-port network is analyzed by simplifying it to two-port networks with other ports matched at the central frequency. Its critical characteristic impedances are then calculated analytically by our derived equations according to the desired differential-mode power division ratio. The maximum achievable power division ratio is 1:4.692 when the characteristic impedances are limited within the realizable range of 20-120 Ω. The impacts of several freely selected design parameters on the operating bandwidth are explored numerically. A prototype is realized by microstrip lines and lumped resistors with the power division ratio of 1:32. The balanced-to-balanced performances of unequal power division, low differential-mode insertion loss, good suppression of common-mode noises, and mode conventions have been demonstrated by the simulated and measured results of the balanced-to-balanced power divider prototype.
TL;DR: In this paper, a simple and low-loss microstrip-to-ridge gap waveguide transition with a very compact geometry is described, in which the height of the air gap in the ridge gap is kept almost equal to the thickness of the substrate of the microstrip line.
Abstract: This letter describes a simple and low-loss microstrip-to-ridge gap waveguide transition with a very compact geometry. The transition transforms the electromagnetic (EM) fields from the microstrip mode to the air-filled ridge gap waveguide mode. This is achievable if the height of the air gap in the ridge gap waveguide is kept almost equal to the thickness of the substrate of the microstrip line. The transition has a pressure contact between the ridge and the microstrip line, so it works without soldering. This is advantageous in systems that require mechanically separable split-blocks or modules and need a lot of transitions. Experimental results of the manufactured back-to-back transition show an insertion loss of 0.32 dB and a return loss of 14.15 dB over 55% relative bandwidth in Ka-band.
TL;DR: In this paper, a microwave sensor for non-destructive measurement of dielectric thickness is presented, which is a quasi-static resonator and based on complementary split ring resonator (CSRR) structure.
Abstract: A microwave sensor for non-destructive measurement of dielectric thickness is presented. The sensor is a quasi-static resonator and based on complementary split ring resonator (CSRR) structure. When the CSRR structure is backed by a conductive medium covered with a dielectric layer the resonance frequency of the CSRR has a strong dependence on the thickness of the dielectric layer. Effect of the size of CSRR sensor on the sensitivity is analyzed numerically. For experimental verification, a CSRR sensor that operates in the 1.6 to 2.3 GHz band is fabricated and excited by a microstrip line.
TL;DR: In this article, a symmetrical coupled-line circuit structure without patterned ground plane is proposed to design tight-coupling high-directivity couplers, which would be found in numerous applications in a microstrip RF front end.
Abstract: A novel symmetrical coupled-line circuit structure without patterned ground plane is proposed to design tight-coupling high-directivity couplers, which would be found in numerous applications in a microstrip RF front end because of its simple structure and inherent excellent compatibility. Based on a traditional even- and odd-mode technique, closed-form mathematical equations for both circuit electrical parameters and scattering parameters are obtained. Due to the use of two coupled-line sections placed in the vertical direction, the directivity of this novel coupler without any other compensation techniques can be enhanced while maintaining tight-coupling performance of almost 3 dB. For demonstrative purposes, three typical full-wave simulation examples with realized physical dimensions in microstrip technology are presented, indicating high directivity and tight coupling coefficient. Finally, a practical microstrip coupled-line coupler is designed and fabricated to operate at approximately 2 GHz. The measured results show good return loss, quadrature phase characteristics, high directivity, and strong coupling performances.
Book•
6 Aug 2013
TL;DR: In this article, the results from a 3D-FEM electromagnetic characterization of microstrip and stripline interconnects with metal filled via fences for isolation are presented, and it is shown that placement of a via hole fence closer than three times the substrate height to the transmission lines increases radiation and coupling.
Abstract: LTCC MCM's for RF and wireless systems often use metal filled via holes to improve isolation between the stripline and microstrip interconnects. In this paper, results from a 3D-FEM electromagnetic characterization of microstrip and stripline interconnects with metal filled via fences for isolation are presented. It is shown that placement of a via hole fence closer than three times the substrate height to the transmission lines increases radiation and coupling. Radiation loss and reflections are increased when a short via fence is used in areas suspected of having high radiation. Also, via posts should not be separated by more than three times the substrate height for low radiation loss, coupling, and suppression of higher order modes in a package.
TL;DR: In this paper, a magnetic field probe with enhanced sensitivity was developed, where an LC resonant circuit was incorporated in a differential-loop probe, together with a Marchand balun, and its equivalent circuit model and design methodology were established.
Abstract: High-sensitive field probes are highly desirable for radio-frequency (RF) interference studies, where ultralow noise levels are of interest. By incorporating an LC resonant circuit in a differential-loop probe, together with a Marchand balun, a magnetic-field probe with enhanced sensitivity is developed. Its equivalent circuit model and design methodology are established. The design is validated by measurements. The measured relative sensitivity in terms of |S21| of the proposed probe increases by approximately 8.63 dB at the resonant frequency of 1.575 GHz compared to that of a conventional design. The advantage of the proposed probe is validated through its application in the measurement of a microstrip trace and a real-world cell phone design.
TL;DR: In this paper, a compact microstrip tri-band bandpass filter (BPF) based on lambda/4$ resonators is proposed, where the first and third passbands are realized by coupling the two dual-band SIRs with synthesized frequency response.
Abstract: This letter presents a novel compact microstrip tri-band bandpass filter (BPF) based on $\lambda/4$ resonators. The first and third passbands are realized by coupling the two dual-band $\lambda/4$ stepped impedance resonators (SIRs) with synthesized frequency response. Meanwhile, the second passband in the middle is achieved by introducing the two coupled $\lambda/4$ uniform impedance resonators (UIRs). A non-uniform coupled-line with the U-folded shape on one line is then proposed to independently achieve the dissimilar external couplings as desired in the tri-passbands. In parallel, the quadruplet topology for each band is formulated by introducing an additional weak I/O cross coupling, thereby bringing one pair of transmission zeros at each side of all the triple passbands, In final, a tri-band BPF with the central frequencies of 1.8, 3.5, and 5.8 GHz, and respective fractional bandwidths of 7.0%, 5.0%, and 3.5% is designed and fabricated. The measured results show good consistence with the simulated ones.
23 Jan 2013
TL;DR: In this article, a new type of microstrip dual-mode dual-band bandpass filter (BPF) using a single quadruple-mode resonator (QMR) is proposed.
Abstract: A new type of microstrip dual-mode dual-band bandpass filter (BPF) using a single quadruple-mode resonator (QMR) is proposed in this paper. The classical even-/odd-mode method is applied to analyze the characteristics of the proposed resonator, which shows that it has two pairs of symmetrical resonant modes. Owing to the inherent characteristic of a dual-mode resonator and source-load coupling, four transmission zeros can be produced and these four resonant modes can be divided in two groups, resulting in a dual-band BPF with two resonant modes in each passband. As examples, two dual-mode dual-band BPFs, Filter A with central frequencies (CFs) at 1.99/5.58 GHz and -3-dB fractional bandwidth (FBW) of 62.3%/19.7%, while Filter B with CFs at 1.64/5.26 GHz and -3-dB FBW of 32.9%/7.6%, are designed and fabricated. An aperture-backed compensation technique is employed in such two filters to enhance the coupling strength between the feeding lines and QMR. Furthermore, a meander coupled-line section is employed in the Filter A design, while a defected microstrip structure is introduced in Filter B design, so as to increase much more design freedoms for tuning filter performance. The fabricated two filters exhibit simple design procedures, low insertion losses, good return losses, sharp shirts, and compact sizes. Moreover, two BPFs do not need external input/output impedance transformation feeding lines.
TL;DR: In this paper, a space difference magnetic near-field probe with three kinds of spatial resolutions is proposed to circumvent the asymmetric electric field coupling into a probe, which will not cancel perfectly even if the structure of this probe is symmetric.
Abstract: To achieve good spatial resolution, small loop size is required in the traditional loop probe. However, the smaller loop size will lead to lower sensitivity for the probe. In addition, loop size is always limited by the minimum line spacing of the fabrication process. Another problem is that the asymmetric electric field coupling into a probe will not be canceled perfectly even if the structure of this probe is symmetric. To circumvent these problems, a space difference magnetic near-field probe with three kinds of spatial resolutions is proposed in this paper. The probe head including a one-turn loop and a two-turn loop is manufactured in low temperature co-fired ceramics (LTCC). The one-turn loop is clamped with the two-turn loop. Two loops are covered with two shielding ground plates to form a tri-plate structure. The received signals from these two loops are outputted with two SMA connectors through two striplines. The flip-chip junctions with low loss and good shielding capability are used between the probe head and the striplines. The probe characteristics are measured using a 436- μm-wide microstrip line with impedance of 50 Ω. Two output ports have different spatial resolutions because two different loops are located above the microstrip line at different height. The proposed probe will have higher spatial resolution when the received signals are outputted in difference. These results are also verified by measuring a 2000- μm-wide straight and a 500- μm-wide meander microstrip line. The experiment results have good agreement with the simulation results and show the resolution improvement of the difference output of the proposed probe for different lines.
TL;DR: In this article, a high gain wideband U-shaped patch antenna with two equal arms on poly tetra fluoro ethylene (PTFE) substrate is presented, which is highly suitable for wireless communications.
Abstract: A high gain wideband U-shaped patch antenna with two equal arms on poly tetra fluoro ethylene (PTFE) substrate is presented. An inverted U-shaped slot is introduced on the circular or square shaped ground plane just under the U-shaped patch. In this communication the effect of size and shape of the ground plane on impedance bandwidth is studied. Maximum impedance bandwidth of 86.79% (4.5–11.4 GHz) is obtained with circular shaped ground plane with diameter 36 mm. The highest gain achieved is 4.1 dBi. The simulated results are confirmed experimentally. The proposed antenna is simple in structure compared to the regular stacked or coplanar parasitic patch antennas. It is highly suitable for wireless communications.
TL;DR: Differential (balanced) microstrip bandpass filters (BPFs) implemented by combining open split ring resonators (OSRRs) and open complementary split ring Resonators (OCSRRs) are proposed in this paper.
Abstract: Differential (balanced) microstrip bandpass filters (BPFs) implemented by combining open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs) are proposed. The OSRRs are series connected in both strips of the differential line, whereas the OCSRRs are paired face-to-face and connected between both line strips in a symmetric configuration. For the differential mode, the OCSRRs are virtually connected to ground and the structure can be modeled, to a first-order approximation, by a cascade of series resonators (OSRRs) alternating with shunt resonators (OCSRRs), i.e., the canonical circuit model of a BPF. These filters have the ability to suppress the common mode by properly adjusting the metallic area surrounding the OCSRRs. An order-3 balanced Chebyshev BPF is designed and fabricated to illustrate the possibilities of the approach. The filter does not require vias (contrary to previous single-ended microstrip BPFs based on OSRRs and OCSRRs), filter dimensions are small, and the common mode is efficiently suppressed with more than 20 dB rejection within the differential filter pass band.
TL;DR: In this paper, a stub-loaded quad-mode resonator with even-odd-mode analysis was proposed to explain the modal characteristics of a dual-band bandpass filter.
Abstract: This letter presents a novel stub-loaded quad-mode resonator Due to the structure geometry, even-odd-mode analysis is applied twice to explain the modal characteristics Each of the four modes equivalent circuits is a quarter-wavelength resonator, so the quad-mode resonator has a compact size The stub-to-stub coupling is introduced to split two identical odd-modes Meanwhile, these two coupling stubs are folded inward, and a new transmission zero is produced, which separates four modes into two parts corresponding to two passbands: the first one is formed by even-modes, and the second one is composed by odd-modes The center frequency and bandwidth of each passband can be controlled by the corresponding physical dimensions For demonstration, a dual-band bandpass filter (BPF) using the proposed quad-mode resonator is designed The simulated and measured results with good agreement are presented
TL;DR: In this article, the authors proposed new symmetric equivalent circuits for 90° and 270° transmission-line sections, with which compact coupled-line ring and branch-line hybrids can be designed and fabricated.
Abstract: New symmetric equivalent circuits are suggested for 90° and 270° transmission-line sections, with which compact coupled-line ring and branch-line hybrids can be designed and fabricated. For this purpose, firstly stepped-impedance transmission-line (SITL) sections, being equivalent to a uniform transmission-line section with arbitrary electrical lengths, are synthesized, and design formulas for the SITL sections are derived. Secondly, three types of equivalent circuits are introduced by combining the SITL sections with coupled-line Π-, modified Π-, or T-type, and are called stepped-impedance coupled-line Π-type (SCΠ ), stepped-impedance modified T-type (SMT), and stepped-impedance modified Π-type (SMΠ). The SCΠs are for 270° transmission-line sections, while both SMTs and SMΠs are for 90° transmission-line sections. Based on the suggested equivalent circuits, compact coupled-line ring and branch-line hybrids designed at 1 GHz are fabricated, and the measured bandwidth of the ring hybrid is 50% with 15-dB return loss. The measured results may be considered as excellent, reflecting their total transmission-line lengths of 183° and 111° for the ring and branch-line hybrids, respectively.
TL;DR: In this article, a class of wide-scan angle wide-band microstrip patch phased arrays is proposed, which are composed of probe-fed microstrip patches backed by substrate-integrated cavities.
Abstract: A class of wide-scan angle wide-band microstrip patch phased arrays is proposed. The proposed phased arrays are composed of probe-fed microstrip patches backed by substrate-integrated cavities. First, a simplified 2-D numerical analysis based on Floquet's theorem is presented to qualitatively demonstrate the E-plane scan performance of the cavity-backed structure compared to that of the conventional microstrip patch phased array. Second, the 3-D scan performance of the proposed phased arrays is thoroughly investigated varying both the substrate thickness and dielectric constant using commercially available EM simulation tools, which is followed by presenting simple design guidelines for the cavity, patch and substrate. A 7 × 7 prototype phased array of the proposed SIW cavity-backed patch structure was fabricated and its measured results agree well with our theoretical prediction and indicate a relatively wide-scan performance when compared to the corresponding microstrip patch phased array without cavities.