Research On Microwave Different-frequency/Same-frequency Power Combining Circuit

With the rapid development of the microwave communication technology,the demand for multi-function circuits is increasing.Different-frequency/same-frequency power combining circuit is an integrated multifunctional circuit that can be used as a multiplexer for frequency band selection and as a power divider for power dividing/combining.Due to its advantages of miniaturization,low loss,high integration,and low cost,scholars at home and abroad have begun to explore it in recent years.In this paper,the design concept of the power divider is integrated into the circuit structure of the diplexer,and some high-performance different-frequency/same-frequency power combining circuits have been proposed.The main researches of this thesis are arranged as follows:1.Using microstrip T-junction as input matching structure,three narrow-band high-selectivity and high-isolation different-frequency/same-frequency power combining circuits have been developed.First,based on the characteristics of the FSIR and the Wilkinson power dividing structure,a multilayer different-frequency/same-frequency power combining circuit with a compact structure has been proposed.Secondly,based on the cross-coupling structure of source and load,the same-frequency power combining circuit is independently located on the bottom substrate,and a multilayer different-frequency/same-frequency power combining circuit with high amplitude and phase consistency has been proposed.Finally,the same-frequency power combining circuit is changed from a Wilkinson structure to a three-line parallel coupling structure,and two air-bridged isolation resistors are loaded.An improved different-frequency/same-frequency power combining circuit implemented on a single-layer substrate has been proposed.2.Based on the center-loaded SIR opening stub multimode resonator,a wide-band different-frequency/same-frequency power combining circuit and a contiguous different-frequency/same-frequency power combining circuit have been developed by using the coupling between the source/load and multiple modes of the resonator.Adjusting the length of the opening stub can produce a transmission zero on both sides of the passband,which is used to improve the frequency selectivity of the passband.The distributed coupling technique is used to connect the two different-frequency channels without any additional matching network.At the same time,the mutual influence of the two channels can be reduced,the independent design of the channels is facilitated,and the circuit structure is simpler to implement.The coupling line is directly loaded on the resonator symmetrically for the same-frequency power output,which replaces the ?/4 transmission line of the traditional power dividing structure,which further improves the integration of the circuit and facilitates the miniaturization of the circuit.