CMOS/IPD switchable bandpass circuit for 28/39 GHz fifth-generation applications

This study presents a switchable bandpass circuit using a standard 0.18 μm complementary metal-oxide semiconductor (CMOS) and an integrated passive device (IPD) technology for fifth-generation (5G) mobile communications. The circuit consists of two IPD bandpass filters (BPFs) and one CMOS single-pole-double-throw switch for the 28 or 39 GHz bands. The broadband switch uses a body-float resistor to improve its insertion loss and power-handling capability. Moreover, the two rectangular ring BPFs not only achieve low losses but also feature good out-of-band rejections. The CMOS chip is then packaged on the IPD substrate with a footprint area of 5.4 mm². The switchable filter results in 4.5/4.7 dB insertion loss, better than 35/30.1 dB isolation, and 18.5/17 dBm input P_{1 dB}.