Microstrip antennas have become a key technology in the field of antennas due to their simple structure, low processing cost, light weight, and many other advantages. Therefore, various performance microstrip antennas are being studied, and omnidirectionality has become a trend in the development of microstrip antennas. For example, using microstrip transmission lines for cross feeding can achieve omnidirectional radiation performance of microstrip antennas. A multi-point excited linear array antenna composed of multiple λ/2 microstrip segments cascaded together. The floor and guide of the microstrip segments are alternately placed on both sides of the dielectric substrate, and the width of the microstrip floor is variable. Cross connections are used to achieve the purpose of inversion. In addition to the transmission mode, there are also radiation modes formed by the discontinuity of cross connection points in this structure. Waves propagate along the inner surface of the conduction band and floor, and the magnitude of radiation is controlled by the width of the floor. To achieve good omnidirectional performance, the width is limited to approximately λ/4. To achieve good radiation efficiency of the antenna, impedance matching can also be performed by adding rectangular patches on each segment of the conduction band to improve the matching by increasing the reactance component.

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