Triple-Band Metamaterial Inspired Antenna for Future Terahertz(THz)Applications

For future healthcare in the terahertz(THz)band,a triple-band microstrip planar antenna integrated with metamaterial(MTM)based on a polyimide substrate is presented.The frequencies of operation are 500,600,and 880 GHz.The triple-band capability is accomplished by etching metamaterial on the patch without affecting the overall antenna size.Instead of a partial ground plane,a full ground plane is used as a buffer to shield the body from back radiation emitted by the antenna.The overall dimension of the proposed antenna is 484×484μm^(2).The antenna’s performance is investigated based on different crucial factors,and excellent results are demonstrated.The gain for the frequencies 500,600,880GHz is 6.41,6.77,10.1 dB,respectively while the efficiency for the same frequencies is 90%,95%,96%,respectively.Further research has been conducted by mounting the presented antenna on a single phantom layer with varying dielectric constants.The results show that the design works equally well with and without the phantom model,in contrast to a partially ground antenna,whose performance is influenced by the presence of the phantom model.As a result,the presented antenna could be helpful for future healthcare applications in the THz band.

Asymmetric Patch Element Reflectarray with Dual Linear and Dual Circular Polarization

A reflectarray antenna consisting of asymmetrical patch elements is proposed,which is capable of producing dual linear and dual circular polarized operation at 26GHz frequency.The main purpose of this design is to support four different polarizations using the same patch element.The proposed reflectarray has a single layer configuration with a linearly polarized feed and circular ring slots in the ground plane.Asymmetric patch element is designed from a square patch element by tilting its one vertical side to some optimized inclination.A wide reflection phase range of 600°is obtained with the asymmetric patch element during unit cell measurements.A 332 element circular aperture reflectarray is designed with the proposed configuration and experimentally validated with a linearly polarized prime feed configuration.Two different orientations of mirror and non-mirror asymmetric patch elements on the surface of reflectarray are analyzed.Dual linear polarization is obtained with the mirror orientation of the asymmetric patch elements on the surface of reflectarray.Alternatively,asymmetric patch elements without mirror orientation are demonstrated to produce dual circular polarization with the same linearly polarized feed.A maximum measured gain of 24.4 dB and 26.1 dB is achieved for dual linear and dual circular polarization,respectively.Their respective measured efficiencies are 28%and 41.3%,which are supported by amaximum−3 dB gain bandwidth of 13.8%and 11.5%.The circular polarization operation of the reflectarray is also supported by a 6 dB axial ratio bandwidth of 9.2%.The proposed asymmetric patch reflectarray antenna with polarization diversity,wide bandwidth and high gain is suitable to be used in many high frequency applications of 5G communication.