An overview of recent progress in the research and development of micromachined devices for use in wireless communication subsystems is presented. Among the specific devices described are tunable micromachined capacitors, integrated high-Q inductors, micromachined low-loss microwave and millimeter-wave filters, low-loss micromechanical switches, microscale vibrating mechanical resonators with Q's in the tens of thousands, and miniature antennas for millimeter-wave applications. Specific applications are reviewed for each of these components with emphasis on methods for miniaturization and performance enhancement of existing and further wireless transceivers.

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Micromachined devices for wireless communications

In this paper, we report on the results of an investigation into dual-mode operation of microstrip triangular patch resonators and their applications for designing dual-mode bandpass filters. It has been found theoretically that the dual modes can result from the rotation and superposition of a fundamental mode. The characteristics of the dual modes and their mode splitting are described. The applications of this new type of dual-mode microstrip patch resonator in the design of microwave planar filter are presented. A circuit model for operation of this type of filter is proposed. Two- and four-pole filters of this type are demonstrated for the first time. Both theoretical and experimental results are presented.

/pdf/theory-and-experiment-of-dual-mode-microstrip-triangular-3caz7riiij.pdf

Theory and experiment of dual-mode microstrip triangular patch resonators and filters

This paper presents the design of a class of highly selective microstrip bandpass filters that consist of microstrip open-loop resonators that exhibit a single pair of attenuation poles at finite frequencies. A practical design technique for this class of filters is introduced, including tables and formulas for accurate and fast filter synthesis. Two design examples of a six-pole filter with a fractional bandwidth of 7.331% at 955 MHz and an eight-pole filter with a fractional bandwidth of 10.359% at 985 MHz are described. Theoretical and experimental results are presented. The compact size and the excellent performance of this class of filters have been demonstrated.

/pdf/design-of-highly-selective-microstrip-bandpass-filters-with-m2f7ovdm1t.pdf

Design of highly selective microstrip bandpass filters with a single pair of attenuation poles at finite frequencies

In this paper we present some results of a primary development of microstrip bandpass filters comprised of triangular patch resonators for high temperature superconducting (HTS), micromachined circuits and other applications. Advantages of a triangular patch resonator filter are not only its higher capability of power handling, but also its natural circuit topology that can inherently implement finite-frequency transmission zeros in a simple cascading structure. In order to have the transmission zeros on the either side of the passband, two different resonant modes of triangular patch resonators are employed. Two three-pole filters of this type, which may form the basic units for higher order filters, are for the first time demonstrated both theoretically and experimentally.

Microstrip triangular patch resonator filters

This paper describes the design and measurement of a planar diplexer integrated on a single silicon substrate. The diplexer channels are 5% and 6.5% relative bandwidth at 28 and 31 GHz, respectively. The diplexer is based on a micropackaged membrane supported capacitively coupled microstrip structure and is 1.5 cm/spl times/1.6 cm and only 1.4 mm thick. The measured insertion loss is 1.4 dB (5%) and 0.9 dB (6.5%) for the two channels with better than 35 dB isolation in the 28 GHz band and better than 50 dB isolation in the 31 GHz band. The measured results include all transition and packaging effects. The diplexer has coplanar-waveguide ports and can easily be integrated with other elements such as planar antennas, low-noise amplifier, and power amplifiers.

A high-performance integrated K-band diplexer

This paper describes the design and the realization of two membrane supported microstrip millimeter-wave planar bandpass filters. Both filters exhibit transmission zeros and a 2.3 dB port-to-port insertion loss for the 37 GHz 3.5% bandwidth 2-pole filter and a 1.5 dB insertion loss for a 60 GHz 8% bandwidth 4-pole filter. The use of membrane technology allows a significant reduction of insertion loss, combined with a reproducible, low cost fabrication process.

D. Crost

Papers

Low loss micromachined filters for millimeter-wave telecommunication systems