Abstract: A far-infrared imaging antenna array has been demonstrated for the first time. The array is a line of evaporated silver bow-tie antennas on a fused-quartz substrate with bismuth-microbolometer detectors. The measured optical transfer function shows that the system is diffraction limited. This imaging array should find direct application in fusion plasma diagnostics. If the microbolometers can be replaced by more sensitive diode detectors, the array should also find application in radiometry and radar.

Abstract: A focal-plane imaging antenna array has been demonstrated at 119 µm The array is a line of evaporated silver bow-tie antennas with bismuth microbolometer detectors on a silicon substrate Radiation is coupled into the array by a lens placed on the back of the substrate The bolometers are thermally isolated from the silicon substrate with a half-micron layer of polyimide The array performance is demonstrated by coherent imaging of a series of holes at half the diffraction-limited cut-off frequency

Abstract: The improvement in SNR and detection range due to distributing an antenna array throughout the airframe and skin of an aircraft is examined. SNR formulas for three system configurations are presented and compared with that of a conventional, monostatic radar. Examples given in the paper show detection range increases as large as a factor of 4. Three additional potential advantages of the distributed array are an increase in spatial signal processing capability, an improvement in azimuthal resolution, and a potential reduction in transmitter power for fixed radar Performance so as to reduce the probability of intercept.

Abstract: A phased array antenna using microstrip for tne AMES (Aeronautical Maritime Engineering Satellite) airborne antenna. The phased array antenna has tested over a frequency range from 1.54 to 1.65 GHz. Scanning abilities up to +30 degrees have been verified over above the frequency range. The V.S.W.R is less than 2 to 1 over 8.4 percent bandwidth. By using the method suppressing the higher modes, the boresight axial ratio has been reduced to less than 0.8 dB.

Abstract: The surface area utilization efficiency of an array of antenna elements distributed over a prescribed geometrical surface is increased by configuring that surface as an ellipse of revolution. Preferably, the ellipsoid surface over which the antenna elements are distributed has a shape such that the major axis of the ellipse in rotation is twice the length of the minor axis. This results in an optimal, near constant illuminated surface area for any angle in the hemisphere. Because a more efficient use of the antenna surface area is provided, the number of antenna elements that is required to obtain the same array gain in all directions in the hemisphere can be reduced substantially when compared with spherical or tetrahedral configurations of conventional hemispherical coverage arrays.

Abstract: A means is described for self-organizing a nonrigid, distributed, transmit-receive antenna array for use in airborne radar. The techniques are applicable to ground-based or shipborne radar as well. Methods are described for initializing the array using various primary microwave illuninators. The description of phase conjugation techniques and means for distributing phase reference to all elements in the array are the central parts of the paper.

Abstract: A monitor determines, from the ground, the orientation (roll and attitude)f a missile by observation of the character of a transmitted signal(s) therefrom. By transmitting to a ground receiver a linearly polarized signal(s), the missile identifies a given plane fixed with respect to its body frame. This plane is identified at the ground receiver by comparing the ratio of the signal(s) received in any two cross-polarized directions. To resolve the attendant 180° ambiguity, the monitor employs an antenna array disposed on the missile that is switchable, back and forth, between two equal power lobes. The monitor operates with a single transmitter, and the simple lobe structure of the transmitted signal(s) is obtained using a linearly polarized antenna array with electronic phase switching between the aforementioned equal power lobes.

Abstract: A radio direction finding system based on the doppler frequency shift principle is disclosed which utilizes a polygonal shaped antenna array and a conventional FM receiver. Voltages from each antenna are combined in an rf summing circuit which may be located remotely from the antenna. Audio output from the FM receiver is processed to measure the phase angle of the commutation frequency phase modulation imparted to the rf receiver input signal by gain variations within the rf summer circuit. Bearing angle proportional to the measured phase angle is displayed in a circular array of light emitting diodes and a three digit decimal display and is provided for recording or remote display through a serial interface.

Abstract: An antenna array comprises a dielectric image waveguide (3) acting as a feeder, which may be of the insular or inverted-strip type, in contact with a dielectric sheet (1). On the sheet (1) is located a plurality of strips (4) of metallizing extending outwards from the feeder-guide (3). The inner ends of the strips are located to couple with the feeder-guide and their outer ends act to radiate or receive most of the power. Preferably the mode propagated in the feeder-guide is an E mn y mode higher than the fundamental, suitably the E 21 y mode.

Abstract: A external feedback network for decreasing variations in a beam pointing angle of a scanning antenna array. A dedicated aperture manifold is intergral with the aperture of the scanning antenna and provides a signal which represents the beam pointing angle. The signal is detected, decoded, and converted into digital data for averaging and processing by a CPU. The processed data is then compared with a value stored in memory and any difference forms the basis of a correction signal. For application to a microwave landing system, the correction signal is used to adjust the start/stop time of the scanning commands of the antenna to remove the error without modifying the beam steering algorithm. A space-coupled monitor may also be used independent of the feedback network to provide an alarm in response to any failure of the dedicated aperture manifold, the automatic stabilization circuitry or the array system.

Abstract: : Measurements have been made on two 7 element azimuthally-symmetric arrays, consisting of one active receiving element mounted at the center of six symmetrically positioned parasitic elements with variable reactive terminations. The measurements were made at frequencies between 15 and 25 MHz on an antenna range. Most of the data was taken on an array of diameter 80 cm (0.05 lambda at the center frequency of 18 MHz) with helically-wound monopole elements. Attempts were made to form the array pattern deterministically by using Harrington's theory to compute the reactive loads necessary to form a pattern lobe in a desired direction. Although the pattern lobe could be steered in the general desired direction, the directivity of the pattern was low and reproducibility poor. The majority of the measurements used the array in an adaptive mode in which the reactive terminations were adjusted manually to minimize one or two incident signals representing undesired interference. The manual adaptation consistently produced sharp spatial notches in the direction of the interference in an otherwise nearly omnidirectional pattern. The notches typically had a width of 50 degrees and depth of 25 to 30 dB below the pattern main lobe; the cancellation bandwidth was 40 kHz. (Author)

Abstract: A method is disclosed whereby adjacent transmitting antenna arrays may be more closely spaced to each other and to receiving antenna arrays while still maintaining a high level of isolation between arrays. In each antenna array, first and second parts thereof are identified. The two parts of each transmitting array are driven in phase quadrature with each other and at substantially equal power levels, and the antenna arrays are spaced sufficiently close to each other so that radiation emitted by one array and received by another array undergoes a cancelling effect before reaching the RF generator associated with the other array. The two parts of each receiver array are coupled to their associated receiver by a signal path such that substantially quadrature phasing is established between the first and second parts thereof to cause received radiation to cancel in the signal path before reaching the receiver.

Abstract: A method of moments solution is presented for the analysis of a large linear antenna array of uniformly spaced thin-wire dipoles parallel to an infinite perfectly conducting plane. A single piecewise sinusoidal expansion and testing function per dipole is used in a Galerkin procedure. This results in a symmetric Toeplitz generalized impedance matrix requiring approximately 2N^{2} multiplications and divisions to determine the unknown dipole currents. The solution corresponds to a savings of a factor of N/6 over a Gaussian elimination solution. Computed results are given for a 1000- element dipole array.

Abstract: A beam forming network for a multielement antenna array includes a sum pattern network (106, 108) for generating signal weights corresponding to a sum antenna pattern having omnidirectional side lobes and a difference pattern network (110) for generating signal weights corresponding to a difference antenna pattern with omnidirectional side lobes. Means (103, 104) are provided to couple energy from the difference pattern network (110) to only a portion of the sum pattern network (108). The signal weights are split by signal splitters (112, 114, 116, 118) and delivered in pairs to output terminals (120-1 to 120-8), one of which (120-8) is terminated in its characteristic impedance (120-8a).

Abstract: This disclosure is concerned with a linear antenna array mounted on a conductive longitudinal boom, as in a Yagi-type array or the like, having a plurality of assymmetrical transversely extending folded half dipoles and linear extensions thereof disposed at successive longitudinally spaced locations along the boom, with the folded half dipoles of successive antennas extending from opposite sides of said boom.

Abstract: A direct relationship between the conventional properties of an antenna array and its performance in an adaptive mode is given. Expressions are provided to obtain the output signal-to-interference-plus-noise ratio (SINR) of an adaptive array in terms of its conventional pattern and the locations of the desired signal and jammers. These expressions permit one to evaluate the performance of an adaptive array without an exhaustive search for all possible scenarios and parametric values to ascertain that the required performance levels would be met. In fact, one can predict the jammer locations for which the array will provide its best and worst performance by observing the conventional pattern.

Abstract: A millimeter-wave imaging antenna array has been demonstrated for the first time at 245GHz. The array is a line of evaporated silver bow-tie antennas on a fused-quartz substrate with bismuth-microbolometer detectors. The measured optical transfer function shows that the system is diffraction-limited. If the microbolometers can be replaced by more sensitive diode detectors, the array should find application in radiometry and radar.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: A teaching is specified for calculating the phase values for each aerial element of the antenna array required to generate a desired antenna directional characteristic, it being assumed that, for given amplitude shading, only the phase shading has to be calculated as the variable. In the past, it was only known for the beam deflection and beam widening to be achieved by phase control of aerial elements. A more wide-reaching beam modification, that is to say beam forming, is made possible for the first time by the invention. The invention can be used, for example, in electronically phase-controlled radar antennas.

Abstract: PURPOSE:To set accurately the extent of the initial phase shift of each phase shifter, by arranging a signal generator at a point separated sufficiently from a plane antenna array to radiate signal radio waves and by measuring them CONSTITUTION:The plane of a plane antenna array is set on the correct horizontal plane, and specially, a reference antenna element 1 and subreference antenna elements 8 and 9 are adjusted accurately for the horizontal level, and the interval between them is adjusted to a design value do accurately A distance (l) between a signal generator 12 and each antenna element 4 is selected in such degree that radio waves are made incident from the signal generator 12 to antenna elements 4 in parallel Phases of receiving radio waves corresponding to all antenna elements 4 are measured simultaneously to calculate correction values to be set to all adjustable phase shifters 5

Abstract: In an antenna array having a multiplicity of differently aligned slotted aerials, the latter are formed by the open waveguide ends of a waveguide junction. The structure of the waveguide junction is advantageously milled completely into a metal base plate which thus forms three sides of the rectangular waveguide. The fourth waveguide side is produced by screwing a cover plate against the base plate. For reasons of stability, and to reduce the antenna dimensions, the complete waveguide junction is filled with a dielectric. An antenna having only two slotted aerials, in which the waveguide junction is formed by a straight waveguide piece, is particularly advantageous.

Abstract: Radio frequency antenna arrays of radiating slot apertures serially connected along a predetermined path transverse to the radiating slot apertures. In the exemplary embodiments, the radiating slot apertures are formed by parallel edges of conductive radiator surfaces where the edges are spaced apart by substantially one-half wavelength at the anticipated antenna operating frequency. Such radiator surfaces are, in some embodiments, dimensioned in a direction parallel to the apertures in relation to the relative proportion of radio frequency energy which is to be radiated to/from the slot apertures associated therewith to thus determine the total array aperture amplitude taper while the spacing between the radiator surfaces determines the phase taper across the total array aperture. Other exemplary embodiments utilize internal reflections in an array to determine the array amplitude taper and still other exemplary embodiments combine a plurality of such arrays to form two-dimensional special purpose arrays.

Abstract: PURPOSE:To shorten time required for calculating the quantity of phase shift, by controlling a phase shifter provided on a monopulse synthesizer terminal of a phased array antenna, together with a built-in phase shifter group for an antenna element, and scanning an antenna beam precisely CONSTITUTION:Scanning angle command signal and a scanning speed command signal are applied to a switching circuit 22 of a beam scanning controller 10 from an information processor As a result, the circuit 22 provides a calculation start command to a moving extent calculating circuit 11 at every 08thetaB, etc of an antenna beam thetaB, simultaneously phase shifters 191-194 provided on 4 terminals of a monopulse synthesizer 18 are controlled through a moving extent calculating circuit 20 and a moving extent driving circuit 21, and scanning is executed precisely for 08thetaB by an antenna array group During this time, the circuit 11 ends its calculation, a built-in phase shifter group 16 is controlled at every antenna array element by a phase shifter driving circuit 13, and the antenna beam moves its scanning by the 08thetaB step Accordingly, as for the quantity of phase shift of all the phase shifters of the antenna element, it is unnecessary to operate every time even in case of precise scanning, and the time required for calculating the quantity of phase shift is shortened substantially

Abstract: : In interference-cancelling antenna array systems where the signals are combined after passing through receivers, the differential frequency responses of the receivers act to limit the null depth and therefore the degree of interference rejection attainable for finite-bandwidth interference. An experimental four-element HF antenna array is used as an illustration; the measured differential frequency dependent phase and amplitude responses of the receivers are presented and the corresponding limits to null-depth derived, for a 3 KHz bandwidth. Correction techniques, including an exact software procedure and a hardware-implementable approach to linear phase correction are presented, and their requirements and anticipated performance considered. (Author)

Abstract: An antenna array comprises a dielectric image waveguide (3) acting as a feeder, which may be of the insular or inverted-strip type, in contact with a dielectric sheet (1). On the sheet (1) is located a plurality of strips (4) of metallising extending outwards from the feeder-guide (3). The inner ends of the strips are located to couple with the feeder-guide and their outer ends act to radiate or receive most of the power. Preferably the mode propagated In the feeder-guide is an mode higher than the fundamental, suitably the mode.

Abstract: PURPOSE:To measure the phase quantity of a reception system in an actually packaged state by inputting an attenuated transmission signal to an antenna array element, and determining the phase quantity of the reception system by the phase quantity of the leakage signal of the element into the reception system and the phase quantity of the output transmission signal of the element. CONSTITUTION:The transmission signal attenuated with an attenuator 20 is applied to an active phased array antenna element 1 without leaking from a circulator 11 and leaks from a circulator 4. It is applied to a phase measuring device 21 to which the transmission signal is applied through a saturation receiving amplifier 5 activated by a switch 7, a circulator 11, etc. Then, the sum of the phase quantity by the transmission and reception systems is detected by the device 21. On the other hand, if the transmission signal of the element 1 is applied via a horn antenna 14 to a phase measuring device 22, the phase quantity of the transmission system is detected, and by the difference in the detected values of both devices 21, 22, the phase quantity of the reception system of the active phased array radar is measured in an actually packaged state.

Abstract: An antenna drive arrangement for a very high frequency omnidirectional range (VOR) navigation system for aircraft. The antenna has two vertically arrayed antenna elements located above a ground plane, and reference and variable phase signals are distributed to each of the antenna elements in amplitude and phase relationship selected to produce a null in the H-component of the radiated field which is substantially tangential to a projection of the ground plane. The null is located in a region of the field disposed radially outwardly of the antenna array.