Phased Array Antenna With Self-Calibration Network and Improved Scanning Performance

In this letter, a phased array antenna with a self-calibration network and improved scanning performance is proposed. For the online calibration, the phased array antenna requires a self-calibration network, which occupies the space between the antenna elements. Besides, the coupling suppression structure for improving the scanning performance of the phased array also needs to be placed between antenna elements. To place these two structures with different functions at the same time, it is a good method to reuse the self-calibration network as the coupling suppression structure. In this letter, one side of metallic vias of the substrate integrated waveguide cavity to suppress the element coupling is replaced by a coupling microstrip line. Such a hybrid structure can not only realize the online calibration function but also improve the scanning performance of the phased array. Moreover, to reduce the dynamic range of the coupling coefficient between the antenna element and the coupling end of the self-calibration network, reactance regulator blocks are employed on the coupling microstrip line. The coupling coefficient is between −17.2 and −24.5 dB in the operating frequency band from 15 to 17 GHz. With the self-calibration network, the gain of the 8 × 8 patch antenna is increased by 1.95 dB, and the sidelobe level is decreased by about 4.20 dB when scanning at −50° in the E-plane.