A High Selectivity and Steep Attenuation Integrated Passive Device On-Chip Filter With Semi-Lumped π-Type Topology and Cross-Coupling Technique

In this letter, a high selectivity integrated passive device (IPD) on-chip bandpass filter with compact size is presented. The modified semi-lumped K inverter is utilized to generate two transmission zeros (TZs) at upper stopband. The semi-lumped $\pi $ type section is designed to achieve another two TZs at the lower stopband. Moreover, cross-coupling technology is also employed to introduce TZ, which can improve the frequency selectivity near the passband and the attenuation level at the stopband. A chip sample is fabricated with gallium arsenide processing with a size $1.125\times 0.565$ mm2. The measurement results show that the center frequency is 27 GHz, the fractional bandwidth is 39%, and the insertion loss (IL) is 1.73 dB.