Wideband signal combining circuit based on multichannel different-/same-frequency power combiner

A wideband signal combining circuit with continuous bandwidth based on multichannel different-/same-frequency power combiner is presented. Two-way signals with the same frequency can be combined to a higher power signal. Two-way signals with different frequencies can be combined into a broadband signal. A stepped impedance resonator (SIR) is used as a multimode resonator. The wider bandwidth is got by SIR. And the selectivity of the two filtering channels is improved by the introduction of SIR stubs, which generate four transmission zeros on both sides of the passbands. The high 3-dB point of the low-frequency channel overlaps with the low 3-dB point of the high-frequency channel. Therefore, the output passband is continuous. The measured frequency ranges of two channels are 1.34-2.21 GHz/2.21-2.87 GHz, respectively, and from 1.46 to 2.74 GHz, the input reflection coefficient is such that the return loss is higher than 15.5 dB. The insertion loss of the two channels is 0.71/1.18 dB, and the measured isolation is higher than 15.4 dB. The measured bandwidth of the combining signal is 1.5 GHz (1.34-2.84 GHz).