Harmonic-suppressed Filters And Power Amplifier Based On Discriminating Coupling

With the rapid development of communication technology,the wireless communication system standard is characterized by high data rate,large user capacity and low power consumption.Microwave circuits with compact size,high efficiency and wide bandwidth have became the focus of domestic and foreign scholars.Microstrip bandpass filter?BPF?is of increasing interest and extensively employed in the RF front-end due to its planar structure and easy integration.This thesis mainly studies the filter using the discriminating coupling and its co-design with power amplifier.Discriminating coupling is that by using the same coupling region,the coupling coefficients at fundamental and harmonic frequencies can be controlled independently.Thereby the spurious passband could be suppressed.The content is summarized as follows:1.Design of balanced miniaturized filter.In order to suppress common-mode noise,balanced filters usually employ stubs or capacitor resistors on the center of resonators,or step impedance resonators,which would cause the large dimensions.The innovation of this thesis is to design the balanced filter by using the discriminating coupling.With the discriminating coupling between feeding lines and resonators and low-temperature cofired ceramics?LTCC?process,a LTCC balanced filter with broad stopband is proposed.It could suppress common-mode signal and the second and third harmonics of differential-mode signal.Firstly,the mechanism of the discriminating coupling is analyzed.Then,a miniaturized balanced filter is designed to suppress both common-mode and differential-mode signals.Finally,the electromagnetic simulation is carried out and validates the proposed methods.This work has authorized a patent for utility model and published a patent for invention.2.Design of filtering power amplifier with wide bandwidth using discriminating coupling.Based on the discriminating coupling,a broadband filtering power amplifier is proposed in this paper.The bandpass filter based on the discriminating coupling is used as the output matching network?OMN?of the power amplifier.The discriminating coupling means that the coupling coefficients of the fundamental and harmonic of the OMN are different.Therefore,the input impedances of the fundamental,second and third harmonic meets the requirements of the extended continuous class F^-1(CCF^-1)power amplifier.At the same time,good frequency selectivity is obtained.The principle of the discriminating coupling,the filter synthesis theory and the equivalent circuit are used to guide the design of filtering power amplifier.The experimental results show that the design has better frequency selectivity,wider bandwidth and higher power added efficiency?PAE?.This work has accepted by the Journal IEEE Transactions on Circuits and Systems I:Regular Papers,and has published a patent for invention and applied for a United States patent.