In this paper, a new microstrip power equalizer based on branch resonator loaded resistor is presented. Fourth-order resonance structure is employed to synthesize the frequency response. The equilibrium depth is 12.4dB. For 7.5GHz–18GHz application, the input and output return loss of the power equalizer is greater than 10dB. By changing the characteristic impedance of the main transmission line, which is connected by the resonance branches, we obtain good standing wave ratio. Because no additional matching transformer is needed, the power equalizer is small and easy to be produced. The power equalizer has been widely used in traveling-wave tube amplifiers.

A novel highpass filter based on complementary split ring resonator (CSRR) is presented, the HPF has two-staged resonators, each resonator is obtained by improving traditional CSRR into rectangle-shaped CSRR. Equivalent circuit of CSRR will be studied in the paper and the HPF will be simulated in HFSS and measured. The HPF has a compact size of 7mm*10mm, its passband covers from 7GHz to 22GHz with an insert loss less than 2dB, the rejection below 6GHz is more than 30dB, which means this HPF has a sharp edge. Simulation results in HFSS and measurement results are greatly matched.

The effect of the microstrip bend on the propagation characteristics of a microstrip line was investigated based on the Finite-Difference Time-Domain（FDTD）method.The dispersive characteristics of a microstrip line with a bend are quite different from that of a uniform straight microstrip line.The effect of bend discontinuity on propagation constants deceases exponentially with the distance form the corner of the bend.This can be explained by the fact that the higher order modes excited by the bend discontinuities have intrinsic properties of exponentially decay with the distance from the bend discontinuities.This effect can be negligible（less than five percent）when the distance is beyond ten times of conductor strip width.The S parameters and propagation constants comparison between unmitered and mitered bends are also presented.The proposed method which takes advantage of the FDTD algorithm and the Root Mean Square Deviation（RMSD）analysis is also an effective way for analyzing the dispersion characteristics of other planar transmission lines.