Development and Testing of 4-element Microstrip Antenna Array

The array antenna is placed at the focal plane of the radio telescope and combined with the beam forming network to observe a sky area at the same time to achieve greater field of view coverage. Because the amplitude and phase of each element need to be adjusted, the array antenna is actually a small phased array. Therefore, during the design of the array in addition to combining the focal field distribution of the telescope and the field of view to be achieved by the telescope, the performance verification of the array itself can refer to the traditional phased array. In this paper a 2×2 rectangular microstrip patch antenna array with element spacing of 0.7 times the wavelength is designed. The measured results show that the S11 of each port is all below -10 dB, and the beam gain after the beamforming of 4 elements is 12.54 dBi. By adding a delay line with a theoretical deviation of 30 degrees to the corresponding element, the beam scanning angle of the array is 28.3 degrees. Although the measured data are slightly different from the simulation results, which is related to array fabrication and feed port welding, the related work has accumulated experience for the design, development and testing of array antenna with more elements, and it has a good guiding significance for performance verification.