New method of analyzing the coupling between patches in planar filters

To have accurate analysis of filters with more than one patch, we should be able to calculate the coupling between patches. This coupling is usually calculated by numerical method such as moment method, which could be very time consuming and not accurate enough. In this paper, a fast and accurate method is presented to analyze the coupling between patches. As an example, a 4-pole dual mode patch filter is analyze with our new method, and result is verified by other methods.