Apollo Microwaves (Canada)

This paper outlines a methodology for assessing breakdown power in guiding structures under varied pressure and gas discharge conditions. Using a rectangular waveguide as an example, analytical equations and advanced electromagnetic simulation tools such as CST and HFSS are employed to evaluate breakdown power accurately. CST-Spark3D simulations demonstrate the impact of different pressures on breakdown power dynamics. Also, Spark3D is used to investigate the multipactor effect in vacuum environ-ments. Our study contributes to understanding breakdown behavior, particularly in space applications, and showcases the efficacy of simulation tools for assessing component reliability.

This paper introduces compact Printed Ridge Gap Waveguide (PRGW) phase shifters tailored for millimeter-wave applications, with a focus on achieving wide operating bandwidth, and improved matching and phase balance compared to single-layer technology. This study proposes a unique approach to achieve the required phase shift in PRGW technology, which has not been previously explored. This study also introduces a novel analytical approach to calculate the cutoff frequency and propagation constant of the PRGW structure, a method not previously addressed. Furthermore, the utilization of multi-layer PRGW technology enables the realization of multi-layer beamforming networks without crossing, thereby supporting wideband operation in a compact size. The proposed design procedure enables the realization of various phase shift values ranging from 0∘ to 135∘ over a broad frequency bandwidth centered at 30 GHz. A 45-degree phase shifter is fabricated and tested, demonstrating a 10 GHz bandwidth (approximately 33% fractional bandwidth) from 25 GHz to 35 GHz. Throughout the operating bandwidth, the phase balance remains within 45 ± 5∘, with a deep matching level of -20 dB. The proposed phase shifter exhibits desirable characteristics, such as compactness, low loss, and low dispersion, making it a suitable choice for millimeter-wave applications, including beyond 5G (B5G) and 6G wireless communications.

The choice of reference planes in the design of the turnstile circulator is not unique. The purpose of this study is to examine two possibilities each of which is equally valid and experimentally verified. One possible arrangement is obtained by replacing the resonator region by a metallic post across the waveguide. The other employs a short-circuit plate tangential to the circumference of the resonator. The main difference between the two solutions is the gap between the open flat face of the resonator and the in-phase piston. The prototype used for this purpose is a novel partially recessed quarter-wave long resonator in half-height waveguide. This study includes the development of a degree-2 circulator using such a junction.

One of the two independent variables entering into the description of the one-port complex gyrator circuit of a junction circulator is its quality factor. The other is the susceptance slope parameter. It determines both its gain bandwidth product and the upper frequency bound of this type of junction. The purpose of this paper is to investigate that of the partially recessed waveguide turnstile circulator using a quarter-wave-long re-entrant gyromagnetic resonator. The quality factor of this class of junction is essentially determined by the gyrotropy of the magnetic insulator, except for the penetration of the resonator into the housing of the junction. The other physical parameter of the junction may therefore be utilized to adjust the susceptance slope parameter of the gyrator circuit. The work undertaken here is in WR75 waveguide at a frequency of 13.25 GHz.

A new configuration has been used for design of a wideband resonator-coupled bandpass filter with high rejection on both sides of the passband. Corrected group delay in combination with space mapping was used to calculate the initial dimensions, which provides a response that is sufficiently close to ideal response in order to be used in full-wave optimization. The design was fabricated and measurements are in excellent agreement with simulation.

Radio communications in the past century have relied primarily on nonlinear devices to modulate and demodulate signals for wireless transmissions. This article reviews initial laboratory results obtained with new radios using linear interferometers to modulate and demodulate ultra-wide-band (UWB) signals. Automotive and chip fabrication industries apply such interferometers in new commercial radios for UWB communications.

One means of tuning planar stripline resonators with top and bottom electric walls and a magnetic sidewall is to include suitable radial and circumferential slots in the resonator plate. The use of a triplet of radial magnetic walls is a standard result in the literature and it has been shown to leave the so-called symmetric pole on the boundary of a planar resonator unperturbed. It is separately understood that a triplet of circumferential magnetic walls in the resonator plate will essentially modify both the dominant symmetric pole and virtual zero only. Both conditions are investigated experimentally. The first-mentioned geometry may enter into the design of three-port circulators using triple impedance poles and the latter in the adjustment of high-quality conventional circulators.

The open dielectric or gyromagnetic post resonator on the axis of a radial waveguides or at the junction of three rectangular waveguides, is a standard problem region in microwave engineering. The paper introduces a new exact formulation of the passband frequencies of such a symmetrical three-port junction. It is based on recognising that such passbands coincide with the condition for which the impedance of a symmetric mode of the post numerically coincides with the admittance of certain pairs of degenerate modes. This condition is used to determine the frequencies of the first two passbands of the junction in the vicinities of the TM/sub 110//sup m/ and TM/sub 210//sup m/ degenerate pairs of modes. The dominant symmetric TM/sub 010//sup e/ mode is instrumental in defining each of these passbands. The calculations undertaken here are compatible with existing full wave analysis of the geometry under consideration, finite element calculations and measurements.