Design of Microstrip Filtering Antenna for Point-to-point Communication of Automated Guided Vehicles

A highly selective planar microstrip filtering antenna for point-to-point communication is proposed in this paper. The bandpass filter is composed of a rectangular split-ring coupling resonator, and a portion of the filter is equivalent to a microstrip monopole antenna. Two rectangular split-ring structures with their openings aligned generate resonant characteristics, and U-shaped microstrip coupling structures are wrapped outside to optimize the passband characteristics. One of the U-shaped microstrip structures is transformed into a one-side bent structure as a radiation unit and serves as the resonant structure of the final stage of the filter, reducing the connection loss between the filter and the antenna. The operating frequency band of the filtering antenna is from 6.38 to 6.63 GHz with a reflection coefficient of less than -10 dB, a fractional bandwidth of 3.8%, and a peak gain of 4.46 dBi. The filtering antenna has excellent frequency selectivity, good out-of-band suppression, high gain, and small device size, in addition to its low cost after system integration. The simulation results are consistent with the experimental test results. The filtering antenna as a novel radio frequency sensor can be applied to the point-to-point communication of automated guided vehicles in the logistics field.