A compact single layer reflectarray antenna based on circular delay-lines for X-band applications

This paper presents a compact single layer reflectarray antenna based on a diagonally notched square patch and a pair of circular delay-lines, for X-band applications. The length and width of circular delay-lines are varied and optimized to attain a linear phase range of more than 600°. The effect of incident angle in TE and TM modes at 0°, 15° and 30° is studied, which offers stable angular phase range. The hybrid Finite Element Boundary Integral (FEBI) method is used for simulation of the whole reflectarray system comprising of 27 × 27 elements and being fabricated on a low cost FR-4 laminate. The measured gain of 24.5 dBi with aperture efficiency of 49.5% is achieved at 10 GHz. The proposed design provides the measured 1-dB gain bandwidth of 12.5% and 3-dB gain bandwidth of 34%. The simulated and measured side-lobe-levels and cross polarizations are less than -25 dB and -40 dB, respectively.