Input characteristics of slot antenna for printed array antennas

Slot antennas coupled with striplines are used as elements of printed slot array antennas constructed on printed circuit boards. The present paper describes theoretical and experimental studies of the input characteristics of slots in microstrip transmission lines. The slot resistance at resonant frequency is calculated using mode functions based on a variational principle and the inverse Fourier transform; the method is also applied to the case of a shield stripline. The input characteristics of slots with open-ended microstrip sections are also studied experimentally and the line length required for matching between the slots and a feed line is established.