Research On Broadband Up-conversion Components In EHF Band

With the further application of microwave communication in recent years,microwave module is developing towards higher frequency and miniaturization.Upconversion module is an indispensable part of transmitter.In this paper,based on multi chip module(MCM),microwave monolithic integrated circuit(MMIC)is tightly connected to realize the miniaturization design of EHF band broadband upconversion module.Firstly,this paper investigates and analyzes the development status of broadband up converter module,determines the main research direction,and introduces the multi chip assembly technology and low temperature co fired ceramic(LTCC)technology,and briefly describes the transmitter theory and basic circuit knowledge.According to the design index,this paper makes a detailed scheme design analysis of the up conversion system,including the selection of frequency conversion scheme,the design of each link and the simulation calculation of the whole system.Secondly,the selection of circuit chip,the design and Simulation of passive components and predistortion linearization module are carried out.The contents include the miniaturization design of two SIW filters and the general design of two-way analog predistortion module.The RF filter is a multi-layer cross coupled SIW filter based on LTCC technology.Six resonators are distributed in a three-layer circuit structure.Compared with the traditional SIW filter,the size of the filter is reduced by nearly 2/3,and it has high selectivity;SIW filter of E-type DGS structure is selected as lo filter,and the method of bidirectional loading DGS structure is adopted to miniaturize the filter.The volume of the filter is reduced by nearly 1/2,achieving better selectivity and lo harmonic suppression;The predistortion module adopts two-way predistortion circuit,and the vector superposition technology enables the analog predistorter to meet the linearization requirements of SSPA and TWTA power amplifiers at the same time.Finally,the layout and cavity of the circuit are designed.The size of the whole circuit is78 mm × 52 mm × 12 mm.Through the test of the whole machine,the gain of the upconverter module is 40 d B,the output flatness is less than ± 1d B,the stray suppression system is more than 50 d Bc,and the VSWR(Abbreviation for Voltage Standing Wave Ratio)of the output port is less than 2,which meets the design requirements.