Design of a Printed monopole Array Antenna with Compact Structure and Omni-directional Patterns

In this paper, a printed monopole array antenna is designed, which is suitable for omnidirectional coverage above conductive carrier. The printed monopole is used as the radiation unit to construct a four unit linear array, and a more stable pattern coverage is realized in the horizontal plane perpendicular to the array axis. The monopole radiator adopts the combination of trapezoidal structure and rectangular structure, and the gradual microstrip line is used to feed it. In order to improve the stability of the pattern, a compact microstrip feed network is designed to ensure the in-phase radiation of each unit. The whole antenna array is realized on a printed circuit, which has simple structure and easy processing. A printed monopole antenna structure operating at 0.5GHz is designed. The electromagnetic simulation results show that in the frequency range of 0.47GHz and 0.55GHz, the voltage standing wave ratio of the printed monopole array antenna is less than 2, the gain is about 3.1dBi and 2.6dBi respectively, and the gain at the center frequency point of 0.5GHz is about 3.7dBi. In the horizontal plane, the rise of the pattern is less than 2.5dB relative to the mean value. The test results of the actual machined antenna show that the monopole subarray antenna proposed in this paper is feasible.