A Novel Multi-Functional Filtering Amplitude/Phase Circuit with Tunable Frequency Using Simple Phase Control Network

A multi-functional filtering amplitude/phase circuit (MFAPC) with tunable frequency is proposed in this paper. It comprises a frequency reconfigurable filtering power divider (RFPD) integrated with a phase control network (PCN) and a wideband 3-dB balun that is directly cascaded. By controlling the PCN built on the two output ports of RFPD, transmission phases at two output ports can be continuously and independently controlled. The two output signals with the same amplitude and variable phases are combined through the 3-dB balun. The combined output signals can undergo either cancellation or vector summation, depending on the signs of the two additional phases introduced by the PCNs. When the signs of the two phases are opposite, controllable filtering attenuation is obtained; when the two transmission phases have the same sign, a variable filtering phase shifter is obtained. Furthermore, independent and simultaneous control of amplitude and phase can be achieved by appropriately controlling the PCN. To demonstrate the idea, a comprehensive analysis is presented with well-agreed experimental verification.