Design Of Ultra Wideband Antennas For 5G Millimeter Wave Applications

With the continuous development and increasing maturity of 5G technology,the research of 5G millimeter wave antenna is also changing day by day.millimeter wave antenna has an extremely wide frequency band range,which brings great convenience to design small size,light weight and modular ultra-wideband antenna.Ultra-wideband antennas were commonly used in military radar in the early days,but with the development and needs of the society,they are more and more widely used in civil applications,so ultra-wideband antennas play an important role in the whole communication field.It is significant to study the millimeter wave ultra-wideband antenna with good impedance matching performance,constant phase center,stable radiation performance and high gain.In this paper,a millimeter-wave single-ridge ultra-wideband H-plane horn antenna based on a substrate integrated waveguide(SIW)is firstly designed to reduce the cutoff frequency of the main mode by the design of the metallized through-hole in the SIW structure,thus widening the operating bandwidth of the horn antenna,and effectively reducing the equivalent impedance of the SIW by the step-height single-ridge structure.The single ridge structure with stepped height effectively reduces the equivalent impedance of SIW,thus reducing the S11 parameter in high frequency band and preventing the directional map splitting at high frequency.The design also achieves the effect of miniaturization and planarization of the antenna,which facilitates the integration of the antenna with planar circuits,reduces the complexity of the antenna and is easy to implement.Then a millimeter wave high gain tapered slot antenna(Tapered Slot Antenna,TSA)based on dielectric lens loading is designed,and the lens is used to enhance the gain and radiation stability of the TSA.The lens consists of a dielectric lens in the TSA radiation aperture region and an airaccelerated region around it.The dielectric lens consists of an array of hyperbolic metal columns,while the air acceleration region consists of an array of air holes.The phase of the electromagnetic waves passing through the lens can be controlled to achieve a uniform planar wavefront over the aperture for improved radiation performance.Simulation and measurement results show that the designed antenna has a real gain improvement of up to 6.4 d B and stable radiation performance in the range of 9 GHz to 26 GHz without increasing the antenna size,and the shift of the main radiation direction is limited to 2 °.In addition,the cross-polarization level is below-20 d B with high fidelity for short pulse radiation in the spectrum up to 30 GHz.