Modeling And Design Of Microwave Digital Phase Shifters

As an important phase control device in phased array radar,microwave digital phase shifter is widely used in various fields.In the traditional phase shifter design,we need to do a lot of repetitive work in the process of simulating or debugging.In order to meet the increasing market demand,the design efficiency of phase shifter needs to be improved.So we can make some special plug-ins for phase shifter designs by using the existing microwave CAD modeling and simulation software,for the sake of effectively shortening the design cycle and reduce the workload of designers.This topic is based on the above guiding ideology.The main contents of this paper are as follows.This paper introduces the research object microwave digital phase shifter,presents the theoretical knowledge of digital phase shifter,including classification,technical indicators,and the analysis of basic phase-shifting circuits,also gives analysis of some improved structures.The working principle of phase shifter is defined from the root,which lays a theoretical foundation for establishing more scientific simulation models.The discrete devices and basic circuits in the digital phase shifter are summarized,the models and simulation analysis of the main discrete devices in the phase shifter are given,including diodes,gold bondwires,beads and SMA connectors,capacitors and inductance,and some key parameters were compared and analyzed.The basic circuit model required in the phase shifter design process is given,including the diode equivalent model,bias circuit,basic types of phase shifting circuit.All modeling work is based on two-dimensional simulation software ADS and three-dimensional simulation software HFSS.Taking using of the DesignGuide platform in the ADS software,plug-ins for the common circuits in the phase shifter are designed to provide convenience and reduce effort for the designers;and almost all HFSS models are established in the form of full parameters,for other designers to use.Based on the models built,the unit and cascade circuits of L-band three-bit multilayer substrate phase shifter and Ku-band seven-bit non-dispersive ceramic substrate phase shifter are designed,and the designs are made into reality.Each unit and multi-bit phase shifter is tested,analyzed and debugged.The results verify the accuracy and feasibility of the previous modeling analysis.Before the design of the cascadecircuit,we first fabricate the typical phase of the unit circuit,and the overall design is made after verifying the feasibility.Before designing the L-band 3-bit multilayer digital phase shifter,we first fabricate the 45° unit phase shifter,and the sample is proved effective,which shows that the simulation design scheme is feasible,then the design and processing of three bit phase shifter is executed.Before the design of the Ku band7-bit non-dispersive ceramic substrate phase shifter,a single switched-line with loaded-line 180° phase shifter and a single reflective-type with loaded-line 11.25° phase shifter are firstly fabricated and proved effective,then a 7-bit phase shifter based on the two existing structures is fabricated.The experimental results show that these phase shifters exhibit excellent microwave performance over the operating bandwidth.