Miniaturized Ultra-Wideband Bandpass Filter With Ultra-Wide Stopband Using π-Type Unit With Inductive Loading on Integrated Passive Device

In this brief, a new miniaturized ultra-wideband (UWB) bandpass filter (BPF) with ultra-wide stopband (UWS) using pi-type unit with inductive loading on integrated passive device (IPD) is proposed. the pi-type with non-periodic response is equivalent to the coupled line with open-ends diagonally for the first time. The proposed compact lumped BPF based on three pi-type units is not only easy to design UWB response without strong coupling, but also has the advantage of the UWS due to the non-periodic phase of the unit. Besides, the high frequency selectivity can be obtained for two transmission zeros near the passband. In final, a prototype with 3-dB fractional bandwidth of 111% is designed and fabricated at 4 GHz (f(0)). The upperstopband attenuation higher than 24 dB is extended to more than 45 GHz (> 11.25f(0)). It occupies only 0.008 lambda(0) x0.032.0, where lambda(0) is the free-space wavelength at f 0.

Automated summary

A new miniaturized UWB bandpass filter with ultra-wide stopband using pi-type unit on IPD is proposed, providing high frequency selectivity and advantage of UWS. The compact BPF design based on non-periodic response of pi-type units shows two transmission zeros near the passband and a prototype with wide fractional bandwidth is fabricated.