• microstrip-array covered waveguide array;
  • matching of arbitrarily excited finite array;
  • moment method with spectral domain Green's functions for multilayer structure

[1] This work rigorously analyzes a periodic microstrip patch array printed on a dielectric slab and placed over an array of open-ended sidewall loaded rectangular waveguides. The method of moments using spectral Green's functions for multilayer structures is employed. The application selected to feature the computed results of this structure is array matching. This work thus investigates the ability of such patch arrays to improve the transmission levels of waveguide arrays over those of uncovered ones. The matching performance is also compared with conventional dielectric sheath-type tuners. Two array operation scenarios are studied: direct radiating phased arrays, and focal plane arrays as feeds for reflectors. Earlier studies of the latter scenario show that the decoupling efficiency tends to be poor at low frequencies, due to the electrical proximity between the waveguide elements. It will be demonstrated here that both forms of matching layers can be tuned to provide good matching at low frequencies. This study has opted to investigate the beneficial effects of the sheet and the patch array over a wide frequency band, rather than its optimization over a selected narrow band. Such optimizations can be done in practice for known specific operating bands.