Frequency Sweep Antenna Array Multi-function, High-efficiency And High-frequency Applications Research

As the development of radar, communication, mobile TV reception in both commercial and military applications, electronic scanning antennas have found many applications and are developing rapidly. Frequency scanning antenna is one kind of electronic scanning antennas, which beam can achieve beam scanning with changes in frequency. In this paper, according to the requirements of the engineering projects, we have designed three frequency scanning antennas.The main contents are listed below:First is a frequency scanning monopulse microstrip antenna array. The array has the frequency scanning performance in one dimension and has the monopulse performance in another dimension. The miniaturized slow-wave structure has been used to achieve the compact structure. The 4×4 microstrip antenna, the slow-wave structure and monopulse comparator are placed on the same layer, resulting in a very compact structure.Second is a 22X8 one dimensional frequency scanning array using hybrid coupling. In the structure, a low loss E-plane bent waveguide is used as slow-wave structure. The microstrip radiating antenna array is fed by a hybrid coupling technology. With this coupling, the energy is coupled from the waveguide slot to the microstrip array through the aperture. The measured results show that the scan angle of this 22 elements array can achieve about 90°within 1GHz bandwidth in X-band. To the low efficiency and deterioration of the side lobe level, the diagnosis of the near field has been investigated. From the experimental results, it is found the deterioration of the antenna performances is caused by the near distance between the feeding network and the antenna elements. For the future work, the multilayer technology can be applied to improve the performances of array.Third is a 77G frequency scanning waveguide slot array. The waveguide slots have been severed as the radiating elements and the curve waveguide has been used as the slow-wave line to feed the radiating elements. The simulated results show that the scan angle of this array can achieve about 34°within 1GHz bandwidth, the side lobe level is all below -15.3dB, and the peak gain is 34.7dBi.