Design and Simulation of a 74 GHz Millimeter-Wave Lens Horn Antenna
Abstract: A lens horn antenna for millimeter wave band is designed. Based on the principle of geometric optics, the geometric relationship between the lens and the horn is established, the independent design variables are reduced, and the antenna is simulated. The results show that when the center frequency of the antenna is 74 GHz, the diameter of the antenna is 38.63 mm; in the frequency band of 72.5-76 GHz, the in-band voltage standing wave ratio VSWR is less than 1.5, the antenna gain is greater than 28 dB, and the E-plane and The half-power beamwidths in the H-plane are less than 6.5o and 8.5o, respectively. The simulation results of the three-dimensional pattern of the horn antenna before and after loading the dielectric lens show that the dielectric lens can reduce the phase error of the horn surface. The designed antenna has good directivity and gain.
Key words: millimeter wave; dielectric lens; horn antenna; geometrical optics principle; gain; phase error
With the rapid development of modern information and wireless communication technology, the original microwave band has become crowded, and there is an urgent need to develop new bands, which makes the fields of millimeter wave, submillimeter wave, and terahertz wave a scientific research and Hot spots for commercial and military applications [1-2]. In addition, millimeter-wave band antennas have particularly stringent requirements on electrical performance parameters, requiring them to have the advantages of wide frequency band, high gain, low side lobes, and miniaturization. Dielectric lens antennas can effectively generate narrow beams with high directivity and low side lobes in the millimeter waveband and submillimeter waveband [3-4]. At the same time, the dielectric material of the lens is low in price, low in energy loss and low in processing accuracy, so it is very suitable for mass production. Therefore, millimeter-wave dielectric lens antennas are being widely used in airborne radar, guidance communication and other fields.
Horn antenna has wider bandwidth than waveguide slot antenna and microstrip antenna [5], and has simple structure, large power capacity, convenient adjustment and use, and reasonable selection of horn size can obtain good radiation characteristics and higher gain [6] ]. However, the length of the large-diameter horn is relatively large, which will bring difficulties to the structural design and installation. In order to shorten the length of the horn, a dielectric lens can be inserted into the horn aperture to sufficiently reduce its length, thereby reducing the phase error of the horn surface.
In this paper, a 74 GHz millimeter-wave lens horn antenna is designed. By establishing the geometric relationship between the horn and the lens and deriving the design equation of the lens, the three-dimensional electromagnetic simulation software HFSS 13.0 is used for modeling and parameter sweeping [8]. The simulation results show that Lens Horn Antenna
It has the characteristics of narrow beam, high gain and low side lobes.
