A Dual-Band Coupled-Line Coupler with Independently Reconfigurable Power division Ratios.

A dual-band power division ratios reconfigurable directional coupler is proposed in this paper. The dual-band operation is realized by introducing a pair of dual-band coupled-line sections at the two ends of a wiggly coupled-line section. To realize the reconfigurability of power division ratios, three pairs of voltage-controlled varactor diodes are loaded on the dual-band coupled-line sections. In this manner, the power division ratios can be simultaneously reconfigured at both operating bands. Also, the power division ratio of the upper band can be independently reconfigured. For demonstration, a dual-band coupler operating at 0.9/3.1 GHz is designed and simulated. The simulated results show that the power division ratio can be reconfigured from 0 to 5 dB at the lower band, and 3 to 10 dB at the upper band. During the reconfiguration process, the isolation is better than 15 dB with phase imbalance less than 3° at both bands.