A method for finding the electric field distribution of microstrip line fed H-slots is described. A transverse resonance technique is first applied to find a second-order approximation of the slot propagation constant, which is then used in the transmission line model for the H-slot. The proposed model for the field distribution can be applied to the transmission line and cavity model analysis of H-slot coupled microstrip antennas
Dr. Dhanesh G. Kurup, A. Rydberg, and M. Himdi, “Transmission line model for field distribution in microstrip line fed H-slots”, IEEE Electronics Letters, vol. 37, pp. 873-874, 2001.