Dual-band dual-polarised microstrip array with fractional frequency ratio

An S/X dual-band dual-polarised shared aperture microstrip array with fractional frequency ratio (FR=1:3.5) is presented. A hybrid feed is adopted in this phased array to improve the isolation. Measured results agree well with the simulation, exhibiting a |S₁₁|≤15 dB bandwidth of 10% in both bands. Good polarisation-isolation and radiation pattern are also confirmed.