A General Mode Matching Technique applied to Bandpass RadomesTMO Progress Report 42-141 May 15, 2000 A High-Q Millimeter-Wave Dielectric-Resonator Bandpass Filter Using Whispering-Gallery Modes Y. Ji,1 X. S. Yao,1 and L. Maleki1 A low-cost millimeter-wave dielectric-resonator lter using a high-order whispering-gallery mode with the coupling of curved microstrip transmission line has been successfully developed for the mode selection in a millimeter-wave optoelectronic oscillator. The achieved 3-dB bandwidth of this lter is 10.5 MHz (loaded quality factor, Q, is about 3,000) or 0.03 percent at 31.5 GHz with a 3-dB insertion loss and more than a 25-dB band-stop attenuation. I. Introduction An optoelectronic oscillator (OEO) recently developed at JPL has the capability to provide an extremely low phase-noise microwave signal by using ber delay [1].……