Low-Loss 4-6 GHz Tunable Filter with 3-Bit High-Q Orthogonal RF-MEMS Capacitance Network

Abstract

Standard Form 298 (Rev. 8/98) REPORT DOCUMENTATION PAGEPrescribed by ANSI Std. Z39.18 Form Approved OMB No. 0704-0188The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to the Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. Abstract-A low loss 4-6 GHz 3-bit tunable filter was designed and fabricated on a quartz substrate. A high-Q 3-bit orthogonal RF-MEMS capacitance network is presented and its significance on the filter Q is discussed. Detailed design equations for the capacitively-loaded coupled open-loop λ/2 resonators and realization of capacitive external coupling with source-load impedance loading are discussed. The measured filter shows an unloaded-Q of 85-170, an insertion loss of 1.5-2.8 dB (including connector loss), and the measured 1-dB bandwidth is 4.35 ± 0.35% over the 4-6 GHz tuning range. The measured IIP3 and 1-dB power compression point at 5.91 GHz are > 40 dBm and 27.5 dBm, respectively. The unloaded Q and insertion loss can be improved to 125-210 and 1.8-1.1 dB with the use of a thicker bottom electrode. To our knowledge, this is the highest Q tunable planar filter to-date at this frequency range. PLEASE DO NOT RETURN YOUR PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S)12