IEEE MTT-S 2008 International Microwave Symposium Technical Program

Session: WE3A	Planar Filter I
Chair:	Chi Wang, Orbital Sciences Corporation
Co-Chair:	Kawthar Zaki, University of Maryland
Abstract:	This session reports on the state-of-the-art in planar microwave filter development. Topics of interest include compact ultra wideband filters and balanced filters.

WE3A-01	A Multi-resolution Channel-Select Filter with Ultra-Wide Frequency Coverage
1605	M. Koochakzadeh¹, A. Abbaspour-Tamijani², ¹Arizona State University, Tempe, United States, ²Arizona State University, Tempe, United States
	A multi-resolution channel select filter topology is proposed for ultra-wideband coverage, as the multi-stage cascade of bimodal filters with self-complementary periodic frequency response. A 4-stage implantation based on PIN diode switches is presented. This prototype covers DC-2.5 GHz in 16 equal bandwidth channels of 156 MHz with a maximum insertion loss of 6.5 dB.

WE3A-02	A Novel Compact Ultra-Wideband Bandpass Filter Using Microstrip Stub-Loaded Dual-Mode Resonator Doublets
1751	Z. Ma¹, W. He², C. Chen³, Y. Kobayashi¹, T. Anada³, ¹Saitama University, Saitama, Japan, ²Shanghai University, Shanghai, China, ³Kanagawa University, Yokohama, Japan
	A novel compact ultra-wideband (UWB) bandpass filter is developed by using microstrip stub-loaded dual-mode resonator doublets. The proposed doublet consists of two parallel but oppositely arranged stub-loaded resonators, and has a significantly widened passband. A UWB filter is designed by cascading three doublets, and eight transmission poles are obtained in its passband. The filter has a passband covering 3.3-10.4GHz, and exhibits sharp attenuations near its passband. The measured frequency response of the filter has a good agreement with the designed one, and the FCC’s indoor limit is satisfied quite well. The minimum strip and gap widths of the filter are larger than 0.1mm. Therefore, critical fabrication precision requirement or complicated backside-aperture-fabrication process is avoided.

WE3A-03	Planar Multimode Resonator Bandpass Filters with Sharp Transition and Wide Stopband
1078	Y. Chiou, Y. Lee, J. Kuo, C. Chen, National Chiao Tung University, Hsinchu, Taiwan
	Planar bandpass filters are contrived with a very sharp transition band and wide stopband based on multimode stepped-impedance resonators (SIRs). The SIR is tapped with two open stubs at its center and two more stubs at the junctions of the low- and high-impedance sections. By properly trimming the stub lengths, the leading five resonances of the SIR have a close proximity and constitute the passband. Besides, two transmission zeros can be created at both upper and lower sides of the passband. It is believed that the SIR has the most resonant modes in comparison with those in open literature. Based on the multimode resonator, a single-resonator bandpass filter with five transmission poles is designed to have a fractional bandwidth of 35%. In addition, by cascading two such resonators, a tenth-order filter is designed, fabricated and measured. Good agreement between simulation and measured results is obtained.

WE3A-04	Rectangular Stubs in Microstrip or Stripline Using V-lines
1020	R. Levy, R. Levy Associates, La Jolla, United States
	The V-line connection of a wide low impedance stub to a high impedance line of narrow width is introduced. It is an alternative to the well known radial line stub geometry, and requires no relatively complicated impedance and phase length calculations. It also shortens the length of filter circuits by a natural meandering of the high impedance main through lines to which the stubs are connected.

WE3A-05	New Differential PSL Coupled Resonator Filters
1380	S. F. Peik, F. A. Langner, Bremen University of Applied Sciences, Bremen, Germany
	A new parallel strip line (PSL) coupled resonator filter is developed for RF applications with differential signalling. A theory for the design of such filters is given. The correct measurement techniques of double-ended (differential) filters with single-ended network analyzers using mixed-mode S-parameters are discussed and measurements on a differential comb-line filter are presented.

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