A design of unequal termination impedance power divider with filtering and out-of-band suppression characteristics

This paper presents a design of unequal termination impedance 3-dB power divider with filtering and out-of-band suppression characteristics. Two transmission poles are appeared in the passband by controlling characteristic impedance of shunt half-wavelength transmission line. For an experimental validation, the proposed 3-dB power divider with an impedance transforming ratio of 3 is designed at the center frequency (f0) of 2.6 GHz. From measurements, the magnitude of S21 and S31 are determined to be -3.8 dB and -3.6 dB at f0. The amplitude division within -3.9 dB is obtained on the bandwidth of 480 MHz (2.4-2.88 GHz). The input and output return losses are higher than 15.58 dB for the same bandwidth. Moreover, the isolation between output ports is higher than 11.4 dB from DC to 7.4 GHz.