Beam Control Method Research On Electronically Steerable Antenna Based On Amplitude Weighted

In recent years, beam control method research on electronically steerable antenna has become the high concerned topic, which can achieve the beam control(also called the pattern synthesis). Now, beam control is usually achieved by controlling amplitude and phase or element position of the antenna array. As we all know, the phased array antenna is controlled by changing the feed phase of the radiating element. However, with the introduction of the phase shifters, the phased array antenna exposed the inadequacies of big volume, high cost, which restricts its development. More and more scholars begin to research the electronically steerable antenna without phase shifter. Up to now, there is little research available on the beam control method of this type of antenna.Aiming at the problem, this paper proposes a novel amplitude-only weighted beam control method based on holographic theory. Only by changing the amplitude of the radiating element without changing the phase and the size parameters of antennas, can we achieve the beam control of electronically steerable antenna. Two kinds of intelligence algorithm including genetic algorithm and holographic theory. are used to achieve the control of main lobe direction, side lobe level and so on. Two kinds of sidelobe suppression mechanism proposed in this paper can reduce targeted sidelobes effectively.The microstrip leaky-wave antenna has the characteristic of low profile, narrow beam, hign antenna efficiency, easy fabrication. Especially, the beam of microstrip leaky-wave antenna has frequency scanning feature which means through loading electronic control materials, microstrip leaky-wave antenna can easily implement electronically scanning feature. To verify the superiority of this method, the paper utilizes the liquid crystal material to design electronically steerable microstrip leaky-wave antenna array. The microstrip LWA array is excited by aperture-coupled, which solves the problem that the liquid crystal can not be separated control. In addition, for the antenna proposed feed network is simple, the size is small.In order to verify the accuracy of the method proposed in this paper, the antenna is feed by mulit-ports of which the amplitude is set based on holographic theory formula. Then we can achieve beam control of electronically steerable microstrip leaky-wave antenna as long as changing the permittivity of liquid crystal according to the relationship between the liquid crystal molecules and amplitude weighted. The antenna designed is able to implement zero passage scanning feature, multi-beam, rectangular beam and complicated pattern synthesis, actual full wave simulation results are in good agreement with those obtained in the theory.