Frequency Reconfigurable Beam Scanning Squarely Modulated Reactance Surface Antenna With Period and Surface Reactance Control

In this study, a novel antenna design is proposed for designing a frequency-reconfigurable wide-angle beam scanning antenna and applied to a squarely modulated reactance surface leaky wave antenna. The antenna beam angle is electronically steered with discretely (rough beam scan) and continuously (precise beam scan) by controlling the antenna’s modulation period and the surface reactance at any fixed frequency, respectively. The design procedure is provided for the squarely modulated reactance surface leaky wave antenna using unit cell composed of parallel microstrip conductors and varactors in between. The antenna’s surface reactance is controlled by the DC bias voltages of the varactors. Based on the dispersion characteristic of the unit cell of the antenna, beam scanning states for different frequencies are designed. Although the operation frequency can be arbitrary, the model antenna is designed for the operation at two different frequencies of 4.6 and 5.8 GHz. It was implemented, and experimented for the demonstration of the proposed method. It is shown by an EM simulation that 72° and 91° of antenna beam scanning can be possible for 4.6 and 5.8 GHz bands, respectively. Also, some of the operational states (beams) are experimentally verified through utilizing DC bias voltages and a switching circuit. The numerical result and experimental result showed good agreement which verifies the proposed antenna design scheme.