This paper is devoted to the design and construction of a novel technique for ferrite tuning of dielectric loaded, dual-mode cavity filters. This is dealt with in two specific areas:i) Improving the technique to realize a high -Q , low loss, dielectric-loaded, dual-mode cavity band-pass filter, using the hybrid 11 HEM 11d mode, ii) Developing techniques to obtain a wide range tuning mechanism, using ferrite materials. The designed dual-mode filters offer unloaded Qu of more than 10,000 with an insertion loss less than 1 dB. It is shown that ferrite tuning is possible either at below resonance or at the above resonance state, depending upon the strength of the applied DC magnetic field. Experimental results showed that due to its lower saturation magnetization YIG offers a wider tuning range compared with Nickel ferrite.

Multipactor breakdown analysis is presented in cylindrical dielectric RESONATOR waveguide filter under its dual-mode behavior. The method of effective electron algorithm with combination of Monte-Carlo method is used to perform the simulation and predict multipactor breakdown thresholds. The breakdown thresholds of the proposed structure are presented for different values of frequency-gap product. The results indicate that increasing the radius of filter increases the RF breakdown threshold. The results are compared with the classic parallel plate waveguides.

One of the most important phenomena to a_ect the motion behavior of Micro RESONATORs is their thermal dependency. This has recently received the attention of researchers widely. A thermal phenomenon has two main effects, the first is damping, due to internal friction, and the second is softening, due to Young's modulus-temperature relationship. In this research work, some theoretical and experimental reported results are used to make a proper model, including thermal phenomena. Two Lorentzian functions are used to describe the restoring and damping forces caused by thermal phenomena. In order to emphasize the thermal effects, a nonlinear model of the MEMS, considering capacitor nonlinearity and mid-plane stretching, has been used. The responses of the system are developed by employing a multiple time scale perturbation method on a non-dimensionalized form of the equations. Frequency response, resonance frequency and peak amplitude are examined by varying the dynamic parameters of the modeled system. Finally, Fuzzy Generalized Cell Mapping (FGCM) is introduced and applied to the Micro RESONATOR's dynamical system behavior. It is then concluded as to how the model uncertainties and different initial conditions can affect the working domain of the system and/or make it pull in instabilities. At the end, it can be seen that FGCM is a useful method for monitoring the working regions of Micro RESONATORs, while varying system parameters.

In this article, an X-band low phase noise dielectric RESONATOR oscillator is investigated. For this purpose, a dielectric RESONATOR as a frequency stabilization section at the almost center frequency of 12 GHz is designed. The active device is a packaged GaAs FET (an ATF-36077 pHEMT). Firstly, the ATF36077 microwave transistor has been biased. The substrate of this nonplanar oscillator is Rogers RT/Duroid 5880. Finally, the dielectric RESONATOR oscillator has been introduced as a series feedback structure. This presented X-band dielectric RESONATOR oscillator, operating at nearly 12 GHz, exhibits a phase noise of -71 dBc/Hz and -133 dBc/Hz at 1-kHz and 1-MHz frequency offset, respectively. Also, the output power level of nearly 7 dBm is achieved. The second and third harmonic power levels are more than 50 dB and 30 dB lower than the main harmonic power level.

Thermoacoustics describes energy conversion processes, activated by interaction temperature oscillation, accompanying the pressure oscillation in a sound wave, with solid boundaries. In ordinary experience this interaction of sound and heat cannot be observed, because of the very low temperature differences, but under suitable conditions, it can be emphasized and amplified to create remarkable thermodynamic effects such as, steep thermal gradients, powerful convective heat fluxes, and strong sound fields. We designed and constructed a simple thermoacoustic refrigerator with an adjustable mechanical RESONATOR, coupled with the acoustic RESONATOR. Our experimental data showed about %10 increase in the efficiency of the refrigeration in comparison with a simple thermoacoustic refrigerator with no mechanical RESONATOR.

This paper presents a novel approach to design a miniaturized ultra-wideband (UWB) microstrip bandpass filter (BPF) with triple notched bands using a multimode RESONATOR (MMR). The MMR is integrated with folded high-impedance interdigital coupled-line structures, enabling the filter to achieve a UWB characteristic while offering independent control over the introduced notched bands to prevent interference with other operating systems. Additionally, the adoption of folded interdigital coupled-line structures significantly reduces the overall dimensions of the filter. The LC equivalent circuits and transfer function of the proposed MMR are extracted to analyze the behavior of the filter. To validate the design, a fabricated prototype of the proposed filter with triple notched bands at 5.4, 8.1, and 10.1 GHz, featuring attenuations exceeding -22 dB, is presented. The measured results demonstrate that the designed filter provides a passband ranging from 4.2 to 12 GHz, along with a wide rejection bandwidth of up to 20 GHz.