Miniature and tunable filters using mems capacitors
- 9 July 2003
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Microwave Theory and Techniques
- Vol. 51 (7), 1878-1885
- https://doi.org/10.1109/tmtt.2003.814317
Abstract
Microelectromechanical system (MEMS) bridge capacitors have been used to design miniature and tunable bandpass filters at 18-22 GHz. Using coplanar waveguide transmission lines on a quartz substrate (/spl epsiv//sub r/ = 3.8, tan/spl delta/ = 0.0002), a miniature three-pole filter was developed with 8.6% bandwidth based on high-Q MEMS bridge capacitors. The miniature filter is approximately 3.5 times smaller than the standard filter with a midband insertion loss of 2.9 dB at 21.1 GHz. The MEMS bridges in this design can also be used as varactors to tune the passband. Such a tunable filter was made on a glass substrate (/spl epsiv//sub r/ = 4.6, tan/spl delta/ = 0.006). Over a tuning range of 14% from 18.6 to 21.4 GHz, the miniature tunable filter has a fractional bandwidth of 7.5 /spl plusmn/ 0.2% and a midband insertion loss of 3.85-4.15 dB. The IIP/sub 3/ of the miniature-tunable filter is measured at 32 dBm for the difference frequency of 50 kHz. The IIP/sub 3/ increases to >50 dBm for difference frequencies greater than 150 kHz. Simple mechanical simulation with a maximum dc and ac (ramp) tuning voltages of 50 V indicates that the filter can tune at a conservative rate of 150-300 MHz//spl mu/s.Keywords
This publication has 24 references indexed in Scilit:
- Reduced size capacitive defect EBG resonatorsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2003
- MEMS switchable interdigital coplanar filterIEEE Transactions on Microwave Theory and Techniques, 2003
- Tunable lumped components with applications to reconfigurable MEMS filtersPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2002
- A Millimeter-wave Tunable Filter Using MEMS VaractorsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2002
- Distributed MEMS transmission lines for tunable filter applicationsInternational Journal of RF and Microwave Computer-Aided Engineering, 2001
- High isolation, planar filters using EBG substratesIEEE Microwave and Wireless Components Letters, 2001
- Compact dual-mode filters for HTS satellite communication systemsIEEE Microwave and Guided Wave Letters, 1998
- Hairpin-comb filters for HTS and other narrow-band applicationsIEEE Transactions on Microwave Theory and Techniques, 1997
- Active varactor tunable bandpass filterIEEE Microwave and Guided Wave Letters, 1993
- Electronically Tunable Microwave Bandpass FiltersIEEE Transactions on Microwave Theory and Techniques, 1982