Computer-aided analysis and design of resonant-cap type microwave IMPATT sources
01 Jun 1997-International Journal of Electronics (Taylor & Francis Group)-Vol. 82, Iss: 6, pp 677-687
TL;DR: A theoretical analysis of a resonant-cap IMPATT oscillator has been performed on the basis of a device-circuit interaction where the resonant cap is considered as a radial-line cavity around the diode as mentioned in this paper.
Abstract: A theoretical analysis of a resonant-cap IMPATT oscillator has been performed on the basis of a device–circuit interaction where the resonant-cap is considered as a radial-line cavity around the diode. the theoretically analysed results have been evaluated through computer-aided solutions. It is found that to obtain the optimum performance of the oscillator with a given device there are optimum cap-circuit dimensions, i.e. a (D–h) combination for which the load impedance terminating the resonant-cap cavity nearly equals the characteristic impedance of the rectangular waveguide in which the resonant-cap is mounted. Also the theoretical computations show that the ratio of the physical cap diameter (D) and cap height (h) to the wavelength of oscillation (λ r ) is nearly 0.36 and 0.08, respectively, while the effective electrical cap radius (r eff) is approximately a eff quarter-wavelength. These results are in good agreement with the previously reported experimentally measured values. the detailed theoretica...
Citations
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01 Jan 2021
TL;DR: In this article, a power module with device and antenna integrated in the same structure using IMPATT diode has been proposed that might have useful applications at THz frequency, where there is no need for transmission line or waveguide to connect the antenna with the oscillator and the integrated structure will also lead to size miniaturization.
Abstract: The basic concept and possible way to realize a novel power module with device and antenna integrated in the same structure using IMPATT diode has been proposed that might have useful applications at THz frequency. The power module judiciously used the idea of resonant-cap cavity for oscillator design normally used at microwave and millimetre–wave frequency, slotted disc for broadband operation and an improvised circular microstrip patch antenna integrated in the same structure. The structure is realizable with fully planer technology with some added steps in the device fabrication process. Since there is no need for transmission line or waveguide to connect the antenna with the oscillator, the transmission loss is minimized and the integrated structure will also lead to size miniaturization. The integrated power module is expected to have many applications especially at THz frequency regime.
2 citations
References
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TL;DR: In this article, the resonant frequency of a planar, circular disc antenna was obtained in analytical form for a printed-circuit board, where the low profile antenna is separated from the ground plane only by a thin layer of dielectric material.
Abstract: The resonant frequency is obtained in analytical form for a planar, circular disc antenna which is etched on a printed-circuit board so that the low-profile antenna is separated from the ground plane only by a thin layer of dielectric material. The formula is found to have an error of less than 2.5 percent when compared with experimental data.
229 citations
TL;DR: In this paper, a cylindrical cavity with magnetic walls is modeled as a circular microstrip antenna element, which can be resonant in the transverse magnetic (TM) modes, assuming a magnetic line current flowing along the perimeter of the disk.
Abstract: The circular microstrip antenna element is formed by a radiating disk closely spaced above a ground plane. It is modeled as a cylindrical cavity with magnetic walls which can be resonant in the transverse magnetic (TM) modes. The far fields and the radiation conductances for different mode structures have been calculated assuming a magnetic line current flowing along the perimeter of the disk. The directivity of a disk antenna excited in the dominant mode is between 4.8 dB and 9.9 dB, depending on the size. Losses, due to imperfect supporting dielectrics and to the finite conductivity of the conductors, have been derived by means of a perturbation technique. Graphs are given for design purposes showing the input impedance, the Q factor, and the radiation efficiency at resonance for different modes and thicknesses. The air-filled microstrip antenna has the highest efficiency and the broadest bandwidth at a given resonant frequency.
188 citations
TL;DR: In this paper, gallium arsenide (GaAs) Gunn diodes having active lengths of 1.8-2.6 µm, bonded into commercially available packages, were operated in full-height waveguides in the V-, E-, and W-(WR-10) bands, using coaxial-bias circuits with a disc-post resonator to provide the required resonance at their fundamental frequency in the range from about 25-65 GHz.
Abstract: Pulsed and CW measurements in the range 26-110 GHz were performed on gallium arsenide (GaAs) Gunn diodes having active lengths of 1.8-2.6 µm, bonded into commercially available packages. The diodes were operated in full-height waveguides in the V-(WR-15), E-(WR-12), and W-(WR- 10) bands, using coaxial-bias circuits aud a disc-post resonator to provide the required resonance at their fundamental frequency in the range from about 25-65 GHz. Frequency and power measurements were performed up to 110 GHz on the fundamental, second, and third harmonics. The main emphasis of this experimental investigation has been the study of frequency changes caused by changes made in the various parameters of the disc, post, diode, diode package, and embedding waveguide sections.
53 citations
TL;DR: A series of measurements at 10 GHz giving the performance of IMPATT diodes obtained when varying the parameters of a cap circuit are presented in this paper, with correctly chosen parameters, the circuit is suitable for operation over a 40% bandwidth.
Abstract: A series of measurements at 10 GHz giving the performance of IMPATT diodes obtained when varying the parameters of a cap circuit are presented. The results indicate that, with correctly chosen parameters, the circuit is suitable for operation over a 40% bandwidth.
45 citations
TL;DR: A series of p-type IMPATT diodes (p+pn+) have been fabricated from epitaxially grown silicon for operation as oscillators at K a -band frequencies as mentioned in this paper.
Abstract: A series of p-type IMPATT diodes (p+pn+) have been fabricated from epitaxially grown silicon for operation as oscillators at K a -band frequencies. A maximum CW output power level of 700 mW at 29.6 GHz, a maximum conversion efficiency of 10.9 percent, and a minimum FM noise parameter, M, of 25 dB have been measured on this series of p-type diodes. A diode oscillating in a variable height radial disk cavity was frequency tuned from 27.5 to 40 GHz, covering the entire K a -band, with a 1.4 dB power variation over the tuning range. The minimum CW output power of this tunable oscillator was 360 mW at 6.5 percent efficiency.
30 citations