E. Chan

Bio: E. Chan is an academic researcher from University of New South Wales. The author has contributed to research in topics: Crossover switch & Redundancy (engineering). The author has an hindex of 1, co-authored 1 publications receiving 22 citations.

Monolithic MEMS T-type Switch for Redundancy Switch Matrix Applications

Abstract: This paper presents a novel approach to monolithically implementing RF MEMS T-type switches for redundancy switch matrix applications. The T-type switch performs three operational states: two turning states and one crossover state. A six-mask fabrication process is adapted to fabricate the proposed design. Novel RF circuits were used to implement the entire system, including series contact cantilever beams, RF crossover, 90 degree turns and four-port cross junctions. The measured results for the entire T-type switch demonstrate an insertion loss of 1.5 dB, a return loss of better than -20 dB and an isolation higher than 28 dB for all states for frequencies up to 30 GHz. To our knowledge, this is the first time an RF MEMS T-type switch has ever been reported.

RF MEMS Satellite Switch Matrices

Abstract: Microelectromechanical systems (MEMS) technology has the potential of replacing many of the radio frequency (RF) components used in to day's satellite communication systems. In many cases, such RF MEMS components would not only substantially reduce size, weight, and power consumption, but also promise superior performance when compared to that of current technologies. The benefits of MEMS technology be come more pronounced for switch matrices because there is a large number of switching elements and, therefore, any size and mass reduction would have large overall impact. Though there has been some controversy on the reliability and lifetime of RF MEMS switches, significant improvements have been made and RF switches with billions of switching cycles have been demonstrated. This article describes the potential applications of RF MEMS switch matrices in the satellite industry, where mass reduction and performance improvement is crucial.

Miniaturized DC–60 GHz RF PCM GeTe-Based Monolithically Integrated Redundancy Switch Matrix Using T-Type Switching Unit Cells

Abstract: This article presents an approach to monolithically implement radio-frequency (RF) phase change material (PCM) germanium telluride (GeTe) T-type switch as a switching unit cell for millimeter-wave (mmWave) redundancy switch matrix applications. The miniature T-type switch demonstrates three states of operation, including one crossover state and two turn states. A seven-layer microfabrication process, including an additional conductive layer to reduce the $RC$ time constant due to the bias network routing, is developed and optimized to fabricate the multiport RF devices. A $4 \times 6$ PCM-based redundancy switch matrix is developed by monolithically integrating four T-type switches in the cascade configuration. Thermal crosstalk in PCM switches is experimentally investigated using submicrometer spatial resolution transient thermal imaging. The presented T-type switch has the device periphery of 0.55 mm $\times \,\,0.55$ mm, while the overall integrated PCM redundancy switch matrix is fabricated with a device footprint of 0.88 mm $\times \,\,1.1$ mm. The measured results of the T-type switches demonstrate an excellent RF performance with lower than 1.6 dB insertion loss, better than 20 dB return loss, and higher than 20 dB isolation in all states from dc–67 GHz. The redundancy switch matrix exhibits an insertion loss less than 3 dB, return loss better than 14 dB, and isolation higher than 20 dB from dc–60 GHz. To the best of our knowledge, this is the first implementation of a PCM-based redundancy switch matrix.

Generalized Multiport Waveguide Switches Based on Multiple Short-Circuit Loads in Power-Divider Junctions

Abstract: This paper presents a new concept for multiport waveguide switches based on short-circuit loads integrated in power-divider ridge-waveguide junctions. The switching is achieved by means of actuating short and open circuit loads in the waveguide path of a ridge waveguide, eliminating the need of bulky rotors, which are typically used in conventional waveguide switches. A complete class of single-pole N -throw switches (N up to 4) is presented based on this concept. Furthermore, the concept is employed to demonstrate highly compact C-, R-, and T-type waveguide switches by integrating different power-divider junctions in a seamless manner. The T-type case involves three states that provide the maximum flexibility for realizing advanced switch matrices for signal routing. A T-type waveguide switch is built and measured for validating the concept. To our knowledge, this paper marks the first time R- and T-type waveguide switches are demonstrated without the need to use a bulky rotary junction.

Monolithic PCM Based Miniaturized T-type RF Switch for Millimeter Wave Redundancy Switch Matrix Applications

Abstract: This paper presents a novel approach to monolithically implement RF phase change material (PCM) germanium telluride (GeTe) T-type switch for millimeter-wave switch matrix applications. The miniature T-type switch demonstrates three states of operation including one cross-over state and two turn-states. A six-layer micro-fabrication process is developed to fabricate the T-type switch. PCM RF series switches are used to route the signal through various RF sections including 90-degree bends and a cross-over junction. The measured results for the proposed T-type switches demonstrate excellent RF performance of less than 0.6 dB insertion loss, better than 20 dB return loss and higher than 20 dB isolation in all states from DC to 67 GHz. To the best of our knowledge, this is the first implementation of PCM based T-type switch ever reported.

A beam steering single-arm rectangular spiral antenna with large azimuth space coverage

Abstract: A novel beam steering single-arm rectangular spiral antenna operating at 3.3 GHz is analyzed using Ansys HFSS. There are 5 switches mounted on the spiral arm. If PIN diodes are used as switches, only one bias signal is required for actuation. Based on different operation of the switches, two cases with maximum beam directions spaced around 1500 in φ-plane are achieved. Both cases have maximum right hand circular polarization (RHCP) gain of approximately 5 dBi and meanwhile cross polarization is suppressed to a very low level. The variation with frequency of the maximum gain, maximum beam direction, and axial ratio is inspected. The proposed design has a 100-MHz bandwidth with good matching, stable maximum beam direction, maximum gain, and circular polarization purity for both cases.