Compact Packaged Diplexer Based on Highly Selective Dual-Mode Bandpass Filter

A cost-effective planar packaged diplexer was designed, fabricated and measured for X and Ku-band applications. The miniaturization and selectivity of the diplexer are achieved by using a dual-mode resonator concept. The packaged diplexer has shown a low insertion loss of 2.6 and 2.95 at 10 GHz and 15 GHz center frequencies, respectively. Four transmissions zeros provided by each channel filter allow a high suppression over the stopband. Finally, the proposed diplexer shows a less than 1.5% center frequency shift over room temperature ranging conditions of -25 ^οC, +25 ^οC and +40 ^οC.