In this letter, a 20-kW-average-power Ka-band TE01 mode gyro-traveling wave tube (gyro-TWT) with a cut-off waveguide section is presented and verified by hot test experiment for the first time. To improve the average output power, the new type gyro-TWT adds a cut-off waveguide in high frequency beam-wave interaction circuits. The large signal nonlinear theory calculations and particle in cell (PIC) simulations show that the new type gyro-TWT has broadband and high-power output performances. The hot test experiment shows that the measured maximum average power is 20.3 kW at 34 GHz, corresponding to a saturated peak power of 169.2 kW, a saturated gain of 52 dB, an efficiency of ~26.9%, and 3 dB bandwidth of 3.2 GHz.

Proof-of-Principle Experiment of a 20-kW-Average-Power Ka-Band Gyro-Traveling Wave Tube With a Cut-Off Waveguide Section

We report the amplification of 250~GHz pulses as short as 260~ps without observation of pulse broadening using a photonic-band-gap circuit gyrotron traveling-wave-amplifier. The gyrotron amplifier operates with 38~dB of device gain and 8~GHz of instantaneous bandwidth. The operational bandwidth of the amplifier can be tuned over 16 GHz by adjusting the operating voltage of the electron beam and the magnetic field. The amplifier uses a 30~cm long photonic-band-gap interaction circuit to confine the desired TE$_{03}$-like operating mode while suppressing lower order modes which can result in undesired oscillations. The circuit gain is $>$55~dB for a beam voltage of 23~kV and a current of 700~mA. These results demonstrate the wide bandwidths and high gain achievable with gyrotron amplifiers. The amplification of picosecond pulses of variable lengths, 260-800~ps, shows good agreement with theory using the coupled dispersion relation and the gain-spectrum of the amplifier as measured with quasi-CW input pulses.

Photonic-Band-Gap Gyrotron Amplifier with Picosecond Pulses

A compact and broadband circular TE01-mode oversized deformed waveguide bend for high-power transmission line is proposed in this article. In order to obtain a circular TE01 mode with high purity output, a deformed waveguide structure, entitled quad-polar waveguide, which can destroy the degeneration between the TE01 and TM11 modes and weak mode conversion inside waveguide bend is introduced. The characterization of quad-polar waveguide and its influence of deformation on the mode spectrum are analyzed. The mode coupling coefficients of quad-polar waveguide are theoretically deduced to investigate the mode conversion inside the waveguide bend. Based on the multimode coupling theory, a broadband oversized waveguide bend with propagation efficiency over 95% from 27.6 to 34.1 GHz is designed. A prototype is fabricated and measured. The average transmission efficiency is over 93% according to the S-parameter measurement. The TE01 mode with high purity output is demonstrated by the near-field test. The high-power performance is investigated by connecting it with a gyrotron traveling-wave tube (gyro-TWT), and the waveguide bend works stably under a maximum output power of 140 kW. In addition to high power and broadband, the proposed waveguide bend features compact, simple structure, and easy to machine.

Theoretical and Experimental Investigations on a Compact and Broadband TE 01 Oversized Deformed Waveguide Bend

A manufacturing study of a 0.372 THz 8-fold (8F) helically corrugated interaction region (HCIR) and measurement of its wave dispersion characteristics are reported. This demonstrates the structure’s suitability as the electron beam / electromagnetic wave interaction region in a high power frequency tunable Gyroresonant THz source. The 8F HCIR has an eigenmode, which is ideal for broadband tuning, created by the coupling of the TE61 and TE23 modes. Maximum power handling of 14 times larger than a 3-fold HCIR at the same frequency is calculated. A TE11 to TE61 7-fold (7F) helically corrugated waveguide (HCW) mode converter, needed to measure the wave dispersion of the 8F HCIR, was designed and constructed. Negative aluminium mandrels of the 7F HCW mode converter and 8F HCIR were manufactured. Copper structures were constructed through electroforming. The measured wave dispersion of the 0.372 THz 8F HCIR agreed well with simulated dispersion characteristics.

/pdf/8-fold-helically-corrugated-interaction-region-for-high-5gsgscdrhz.pdf

8-Fold Helically Corrugated Interaction Region for High Power Gyroresonant THz Sources

A novel type of frequency doubling gyrotron traveling wave amplifier (FD-GTWT) for applications that require high-power microwave in the sub-THz frequency range is presented. The proposed FD-GTWT delivers high power and high gain over a broad bandwidth and simultaneously doubling the frequency of the input signal. Simulations of a first 263GHz FD-GTWT design are presented, which show for a 10mW driving signal at 131.5GHz an RF output power of 250W at 263GHz and a gain of >40dB over a bandwidth of 17.5GHz. The basis of the FD-GTWT are two interaction circuits separated by a long drift section. In the first circuit, the electron beam is pre-bunched at the fundamental cyclotron harmonic. In the second one, high-power RF is induced by the pre-bunched electron beam at the 2nd cyclotron harmonic. Both sections consist of helically corrugated waveguides that efficiently suppress parasitic interactions and allow broad bandwidth.

New Type of Sub-THz Frequency-Doubling Gyro-TWT With Helically Corrugated Circuit

The frequency agility of a ${W}$ -band gyrotron travelling wave amplifier (gyro-TWA) was demonstrated by the amplification of a frequency-swept input signal (chirp signal). The gyro-TWA was developed to provide high output power and wide bandwidth by using a helically corrugated interaction region. In the experiment a ~0.5-W signal of linearly swept frequency bandwidth of 1 GHz was amplified and a gain of over 30 dB was measured when driven by a 40 keV, 1.5 A, and axis-encircling electron beam.

Amplification of Frequency-Swept Signals in a $W$ -Band Gyrotron Travelling Wave Amplifier

A W-band gyrotron traveling wave amplifier (gyro-TWA) based on a helically corrugated interaction region achieved an unsaturated output power of 3.4 kW with a gain of up to 37 dB and a 3 dB frequency bandwidth of at least 5.5 GHz. In the experiments it was found that the gyro- TWA can be operated with a range of different electron beams. Also the frequency agility of the gyro- TWA was demonstrated by the amplification of multi-frequency signals.

/pdf/amplification-of-w-band-multi-frequency-signals-using-a-gyro-54cutlaf0t.pdf

Amplification of W-band multi-frequency signals using a gyro-TWA

Following on from the successful operation of a broadband, high-power gyrotron traveling wave amplifier (gyro-TWA) in W-band, experiments were carried out to demonstrate the versatility of the gyro-TWA and investigate its tuning characteristics. When operating at a lower voltage of 40 kV, 30 dB gain was achieved for a 1 GHz bandwidth frequency-swept input signal.

/pdf/characteristic-measurements-of-a-wideband-gyro-twa-operating-570bex8xa9.pdf

Characteristic measurements of a wideband gyro-TWA operating in W-band

A W-band gyro-TWA has been developed to provide high output power and wide bandwidth. This letter presents the upgrade of the input signal generation of the W-band gyro-TWA, and the experiment results with frequency-swept input signals. The results show a 30 dB gain was achieved at a 1 GHz bandwidth input signal when the gyro-TWA was driven by a 40kV, 1.5 A electron beam.

/pdf/measurement-of-w-band-gyro-twa-with-wide-bandwidth-input-2ng4vj5dtq.pdf

Measurement of W-band gyro-TWA with wide bandwidth input signal

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Peter Cain

Author Tools

Chat about Author

Papers

Amplification of Frequency-Swept Signals in a $W$ -Band Gyrotron Travelling Wave Amplifier

Amplification of W-band multi-frequency signals using a gyro-TWA

Characteristic measurements of a wideband gyro-TWA operating in W-band

Measurement of W-band gyro-TWA with wide bandwidth input signal