Theoretical and experimental performance of a wideband wide-scan-angle rectangular waveguide phased array (for radar application)

A wideband wide-scan-angle phased array using rectangular waveguides as radiating elements is described. The design, theoretical performance, and experimental verification of the wideband phased array are presented. The verification of scan performance was performed on a 15*15 element array and included element pattern and mutual coupling measurements. The array will be applied in a multifunction active phased array radar codenamed EXPAR. Oepn-ended waveguide elements were preferred above printed circuit dipole and stripline notch radiators because of their accurately predictable performance and good cross polarization behavior in an array environment. A unique feature that favors the waveguide element is its highpass filter characteristics due to the cutoff frequency of the waveguide modes