Impedance of a radiating slot in the ground plane of a microstripline

An expression for the complex admittance of a radiating slot in the ground plane of a microstripline is obtained from the complex radiated power and discontinuity in the modal voltage. The complex radiated power is obtained from the angular spectrum of plane waves. The electric field distribution in the microstripline, required for the determination of the discontinuity in the modal voltage, is determined from the analysis presented by Yamashita and Atsuki. The theoretical results are compared with experimental data.