We present a general theory for designing realistic omega-type bianisotropicmetasurfaces (O-BMSs), unlocking their full potential for moldingelectromagnetic fields. These metasurfaces, characterized by electric surfaceimpedance, magnetic surface admittance, and magnetoelectric couplingcoefficient, were previously considered for wavefront manipulation. However,previous reports mainly considered plane-wave excitations, and implementationsincluded cumbersome metallic features. In this work, we prove that any fieldtransformation which locally conserves real power can be implemented viapassive and lossless meta-atoms characterized by closed-form expressions; thisallows rigorous incorporation of arbitrary source and scatteringconfigurations. Subsequently, we show that O-BMS meta-atoms can be implementedusing an asymmetric stack of three impedance sheets, an appealing structure forprinted circuit board fabrication. Our formulation reveals that, as opposed toHuygens' metasurfaces (HMSs), which exhibit negligible magnetoelectriccoupling, O-BMSs are not limited to controlling the phase of transmittedfields, but can rather achieve high level of control over the amplitude andphase of reflected fields. This is demonstrated by designing O-BMSs forreflectionless wide-angle refraction, independent surface-wave guiding, and ahighly-directive low-profile antenna, verified with full-wave simulations. Thisstraightforward methodology facilitates development of O-BMS-based devices forcontrolling the near and far fields of arbitrary sources in complex scatteringconfigurations.
展开▼
