Dual‐band balanced coupler with wideband common‐mode suppression

Abstract

A novel compact dual-band balanced coupler with differential-mode power division, broadband common-mode, and common-to-differential-mode conversion suppression is proposed. In these double-functionality balanced-coupler architectures, double-sided parallel-strip line 180° phase inverters are used to realize the broadband common-mode rejection. Moreover, the frequency is tunable by changing the characteristic impedance of the transmission line. For practical verification, a balanced couplers (εr = 2.65, h = 0.5 mm, tan(δD) = 0.003) operation at 0.9/1.8 GHz is constructed in microstrip technology and tested.