A compact 5G band N77 bandpass filter with multiple zeros based on GaAs integrated passive device process

Abstract

In this paper, a compact 5G band N77 bandpass filter (BPF) with multiple zeros is designed based on GaAs integrated passive device (IPD) process. The BPF consists of lumped capacitors and inductors. Hybrid resonator technology which consists of a combination of shunt and series resonant tanks are proposed to produce six transmission zeros in the stopband and significantly improve the filter selectivity. In addition, a series resonator at the output port of the filter was introduced to produce another transmission zero at the upper stopband and further improve the stopband suppression. Meanwhile, to reduce the area and insertion loss of the filter, a stacked inductor is designed by using IPD technology, which can greatly reduce the area and size of the filter. The minimum insertion loss is 1.782 dB. The size of the entire BPF is 1.3 mm × 0.7 mm.

Miniaturized IPD bandpass filter design with high out‐of‐band rejection for 5G applications

“…To enhance the out-of-band rejection of the bandpass filters, there are some effective methods by adding transmission zeros (TZs). 1,5,6 In Reference, 5 stepped-impedance stubs embedded in coupled lines are used to introduce TZs on both sides of the filter passband and improve the selectivity. However, the device sizes were relatively large since the LTCC technology was used.…”

“…Integrated passive device (IPD) technology is a promising one to achieve high performance in a very compact circuit size. 1 A novel method to design a BPF from an intertwined circular spiral inductor was proposed. 2 Moreover, a design methodology using π-type unit with inductive loading on integrated passive device has also been proposed.…”

“…In addition to adding TZs to the filter, increasing the filter order is also an effective way to improve the filter performance. 1,6 In Reference, 6 stepped-impedance multimode resonator is employed to achieve an ultra-wide upper stopband attenuation. In Reference, 1 a hybrid resonant cavity technique, which produces six TZs in the stopband, was used to greatly improve the filter selectivity.…”

“…However, all the proposed approaches cannot effectively control the out‐of‐band rejection and the steepness of the passband edges of the bandpass filters. To enhance the out‐of‐band rejection of the bandpass filters, there are some effective methods by adding transmission zeros (TZs) 1,5,6 . In Reference, 5 stepped‐impedance stubs embedded in coupled lines are used to introduce TZs on both sides of the filter passband and improve the selectivity.…”

“…In Reference, 6 stepped‐impedance multimode resonator is employed to achieve an ultra‐wide upper stopband attenuation. In Reference, 1 a hybrid resonant cavity technique, which produces six TZs in the stopband, was used to greatly improve the filter selectivity. Another way to improve out‐of‐band rejection is to add an additional filter circuit 7–9 .…”