An analysis of balun in multimode feed network

In this paper, the impedance convertor in the multimode feed network is considered as a balun. By applying with the analysis method of the asymmetrical (current) bifilar even transmission line, the analysis for the characteristic of impedance transform and output balance of balun are done. It also gives the results, which is in good agreement with the metrical values. This provides the elaborate foundation for the device, modeling and optimize of the multimode feed network.