RF Antenna Adaptive Impedance Matching Based On Chaotic Particle Swarm Optimization Method

With the rapid development of wireless communication technology, frequencyranges used in communications equipments is wider and wider, the requirements ofRF antenna performance are also getting higher and higher.Antenna load will changewith the environment, it is easy to cause the impedance mismatch, affecting thequality of signal transmission, leading to the decrease of the efficiency of powertransmission, therefore fast adaptive impedance matching is of great significance.In order to reduce RF antenna energy reflection and increase the powertransmission efficiency, an adaptive impedance matching method based on chaoticparticle swarm optimization has been proposed in the paper. Its primary work isshown as follows:To avoid premature convergence, the chaotic perturbation is applied to the PSOalgorithm and the CPSO algorithm is designed. Then the standard test functions areused to test its convergence precision and convergence speed, as well asglobal optimal ability. The results are compared to QPSO amd SPSO algorithm testedin the same experimental environment and analysis is done.Narrowband impedance match is done at different frequency and different load.Single-target Chaotic Particle Swarm Optimization is applied to the ideal π-typenetwork impedance matching, and dual-target Chaotic Particle Swarm Optimization isapplied to determine parameter values of the non-ideal π type and dual-stage modelfor realizing wideband impedance matching. It proves that the proposed chaoticparticle swarm impedance matching is adaptive for the basis of broadband impedancematching.Combined with real frequency method, broadband impedance matchingexperiments are done with a variety of operating band. A single target chaotic particleswarm optimization is used to achieve the ideal π-type broadband impedancematching network, and then double objective chaotic particle swarm optimization isused to achieve non-ideal π-type and non-ideal dual-stages model broadbandimpedance matching, proving that the method of uing the dual-stage model anddouble target chaotic particle swarm optimization is more suitable to realizebroadband impedance matching. .Broadband impedance matching is realized with the GSM-1800, UMTS and LTEoperating band respectively. By increasing the sampling points, adjusting theobjective fittness function of CPSO algorithm, multi-band impedance matching isachieved with GSM-1800and UMTS mixing bands, UMTS and LTE mixing bands.Moreover, the higher test band covers GSM-1800, UMTS and LTE mixing bands. Theresults are found to dynamically match the antenna impedance to the RF front-endwith this technique in various bandwide and changed load.