The Research Of The Plat End-fire Antenna Array With Low-side Lobe

As the plat end-fire antenna has a lot of advantage, such as easy facture, low cost, easyproduction and small air resistance. End-fire antenna can be installed at aircraft wing andair abdomen, because it uses reasonably aircraft frame and does not occupy aircraft innerspace, it has been abroad suited for high speed aircraft to realize conformal antenna.However traditional end-fire antenna is middle gain antenna and it not suit to be adopted ina radar system. In order to achieve high gain of plat end-fire antenna, we research onend-fire antenna array. We find the array form has strong mutual coupling which affect theperformance of the end-fire element badly. In this paper, grating lobe suppression of platend-fire antenna array based on orthogonal signal is studied when the element spacing ismore than1.5wavelengths.Firstly, the effect of mutual coupling on end-fire antenna and antenna array werestudied. When the plate end-fire antenna array build up along the sideward direction, theeffect of the different transmitting signal on mutual coupling was analyzed. The methodthat comparing the correct DBF beam pattern with CST simulation beam pattern, whichanalyze the mutual coupling between end-fire elements is proposed. Simulation resultsverify orthogonal signal has suppression effect on mutual coupling.Secondly, the plat end-fire antenna array based on orthogonal signal was studied. Thedifferences of the space energy, the probability of Intercept-LPI, transmitting antenna arraybeam pattern, whole antenna array beam pattern between this antenna array and normalantenna array were analyzed. Based on calculating the phase shift of antenna array, digitalbeamforming technology based on orthogonal signal was studied, Simulation results verifyit.Thirdly, the grating lobe suppression based on virtual array algorithm was studied.Based on studying the feasibility of normal virtual array algorithm in the condition of theelement spacing is1.5wavelengths, when the transmitting and receiving element spacing is1.5wavelengths, a new method of suppressing grating lobe and high side-lode based on thevirtual array algorithm based on least squares estimator is proposed. Experiment resultsvalidate that virtual array has same gain with actual array and main beam width, but SLL ofvirtual array is reduced to-18.25dB from-8.35dB of actual array. Grating lobe and highside-lode is suppressed effectively.Finally, based on studying the mechanism of producing grating lobe and the effect of interfering signal on grating lobe, when the end-fire antenna array is powered byorthogonal signal, a new method of grating lobe suppression is proposed. When thetransmitting array produce grating lobe, a new method of producing low side-lode in thesame position of grating lobe in receiving beam pattern. Furthermore, the whole beampattern can suppress grating lobe and high side-lobe. Simulation results verify the newmethod.