Peripherally Excited Phased Array Architecture for Beam Steering with Reduced Number of Active Elements

Microwave Huygens’ Metasurfaces: Fundamentals and Applications

“…For example, thin active Huygens' metasurfaces can be used for cloaking [78], wavefront and beam synthesis in cavities for microwave sub-wavelength imaging and medical therapy, as well as exterior cloaking [79]. An emerging exciting concept is the use of apertures with only active-element excitations in their periphery for beam steering (through the equivalence principle) to drastically reduce the number of active elements form N 2 to N (albeit with a reduced scan range) [74]- [76]. Another emerging area is that of optically transparent metasurfaces for enhancing or manipulating wave propagation for fifth-generation (5G) signals in smart buildings or smart cars, e.g., using nanometer-scale silver films [80].…”

“…In particular, Wong et al have demonstrated the generation of propagating plane waves inside a metallic cavity by peripherally placing current strips in close proximity to the cavity walls. Recently, the idea of the Huygens' box was further developed to realize peripherally-excited phased arrays [74]- [76]. By synthesizing various propagating plane waves inside a Huygens' box and perforating its top plate to allow radiation, researchers have demonstrated steering of a pencil beam and generation of multiple beams with significantly reduced number of active components compared to traditional phased arrays albeit with a reduction of the scanning angular space [74]- [76].…”

High Gain Periodic 2-D Leaky-Wave Antenna With Backward Radiation for Millimeter-Wave Band

“…The antenna has large size as it resembles radial line slot antennas (RLSA). In [24], a peripherally excited 2D phased array architecture is presented. The excitation of the phased array is achieved by exciting the premiter of the phased array area instead of exciting each element of the phased array, thus reducing the number of the required active elements.…”

A Continuously Tunable Phase Shifter Using Surface Waves

“…In the former, continuously tunable electronic components such as varactors, MEMS capacitors, and tunable substrates are used in order to provide an uninterrupted phase shift range to the input signal. These phase shifters can be used for continuous beam steering [8]- [10]. On the other hand, electronic switches can be used to provide discrete phase shifts with certain intervals [11]- [13].…”