Unequal Single-Ended-to-Balanced Power Divider with Enhanced Input-Matching Bandwidth

Abstract

To reduce the circuit size of a single-ended-to-balanced power divider, a section of coupled line with a short-circuited terminal is applied. In this structure, two transmission zeros are generated, which realizes a wide input-matching bandwidth without extra absorbing branches. The enhanced input matching bandwidth can decrease the effect of the reflection wave power on the operation of the preceding active stage in the RF front end. Equations are derived to support the power transmission in a specific power division ratio. To verify the proposed structure, a single-ended-to-balanced power divider operating at 2.0 GHz is designed, fabricated, and measured. A wide matching bandwidth under �10 dB covers from 0.292 to 3.966 GHz with a fractional bandwidth (FBW) of 183.7%. Simulation and measurement results are in good agreement.