Design and Measurement of a 1-bit Reconfigurable Transmitarray With Subwavelength H-Shaped Coupling Slot Elements

A novel 1-bit 256-element reconfigurable transmitarray antenna (RTA) at the Ku-band is presented. The element consists of two orthogonal H-shaped slots as receiving and transmitting structures, and the power transmission is realized by a coupling microstrip line in between. Two p-i-n diodes integrated on the coupling line can be electronically controlled to reverse the excitation directions, thus generating two states with 180 degrees phase difference and low transmission loss. A subwavelength element spacing of lambda(0)/3 is utilized to stabilize the element performance under oblique incidence. A transmitarray prototype with 16 x16 elements and aperture size of 5.3 lambda(0) x5.3 lambda(0) at 12.5 GHz is fabricated and measured for the experimental verification. The measured results show that the maximum gain is 17.0 dBi with an aperture efficiency of 14.0%, and 2-D scanning beams within +/- 50 degrees angular range are obtained. The 3-dB gain bandwidth of the broadside beam is 9.6%.