Wide-gap re-entrant cavity resonators for 900-1500 MHz

et al. 2014

A piezoelectric voltage coupled microwave reentrant cavity has been developed. The central cavity post is bonded to a piezoelectric actuator allowing the voltage control of small post displacements over a high dynamic range. We show that such a cavity can be implemented as a voltage tunable resonator, a transducer for exciting and measuring mechanical modes of the structure, and a transducer for measuring comparative sensitivity of the piezoelectric material. Experiments were conducted at room and cryogenic temperatures with results verified using Finite Element software.

Section: Introductionmentioning

confidence: 99%

Piezoelectric voltage coupled reentrant cavity resonator

Carvalho

et al. 2014

“…Development of more and more accurate structure modelling based on lumped element analysis [63][64][65][66][67] made it very valuable for making small size high-Q resonators. These are designed for filtering applications at room and cryogenic temperatures, 68,69 displacement sensors for gravitational bar detectors [70][71][72] They have also been used to develop Gunn diodes 73 oscillators, electron beam tubes, 74 and millimetre wave resonators. 75 The electromagnetic field pattern of the re-entrant cavity fundamental mode presents a very high capacitance between the internal post and the lid of the cavity, shown in Figure 5.…”

Section: Re-entrant Cavity Modesmentioning

confidence: 99%

Invited Article: Dielectric material characterization techniques and designs of high-Q resonators for applications from micro to millimeter-waves frequencies applicable at room and cryogenic temperatures

Humbert

et al. 2014

Dielectric resonators are key elements in many applications in micro to millimeter wave circuits, including ultra-narrow band filters and frequency-determining components for precision frequency synthesis. Distributed-layered and bulk low-loss crystalline and polycrystalline dielectric structures have become very important for building these devices. Proper design requires careful electromagnetic characterization of low-loss material properties. This includes exact simulation with precision numerical software and precise measurements of resonant modes. For example, we have developed the Whispering Gallery mode technique for microwave applications, which has now become the standard for characterizing low-loss structures. This paper will give some of the most common characterization techniques used in the micro to millimeter wave regime at room and cryogenic temperatures for designing high-Q dielectric loaded cavities.

“…Microwave re-entrant cavities have been studied over 50 years for a variety of applications. The development of accurate structure modeling based on lumped element analysis [1][2][3][4][5][6][7] has made them very valuable for creating small volume high-Q resonators for filtering applications from room to cryogenic temperatures in comparison with large Whispering Gallery and Bragg mode resonant cavities [6][7][8][9][10][11]. Re-entrant cavities have also been used for producing displacement sensors for gravitational bar detectors [12][13][14][15][16][17], oscillators using Gunn diodes [18] and electron beam tubes [18], and for millimetre wave resonators [20][21].…”

Section: Introductionmentioning

confidence: 99%

Rigorous analysis of highly tunable cylindrical transverse magnetic mode re-entrant cavities

Aubourg

et al. 2013

Cylindrical re-entrant cavities are unique three-dimensional structures that resonate with their electric and magnetic fields in separate parts of the cavity. To further understand these devices, we undertake rigorous analysis of the properties of the resonance using "in-house" developed Finite Element Method (FEM) software capable of dealing with small gap structures of extreme aspect ratio. Comparisons between the FEM method and experiments are consistent and we illustrate where predictions using established lumped element models work well and where they are limited. With the aid of the modeling we design a highly tunable cavity that can be tuned from 2 GHz to 22 GHz just by inserting a post into a fixed dimensioned cylindrical cavity. We show this is possible, as the mode structure transforms from a re-entrant mode during the tuning process to a standard cylindrical transverse magnetic mode.