Adaptive Research And Analysis Of Conformal Array Antennas

The conformal array is usually mounted on the surface of aircrafts and some other high-speed mobile platforms. Its major advantages are not only the aerodynamics of the aircraft can almost not changed and facilitated to install, but also able to reduce Radar Cross Section (RCS) and improve the performance of stealth."Shadow effect"have to be considered in practical application, which means not all of elements can receive the signal from special direction. In this dissertation, some algorithms and techniques of digital beamforming (DBF) based on the conformal array are studied. The pattern function of cylindrical array, truncated conic array and hemispheric array are deduced, digital beamforming research of above-mentioned array are simulated in ideal conditions without"shadow effect". And"shadow effect"is also considered in beam forming with directional elements and compared with ideal condition. The main work includes:Firstly, the model of adaptive antenna system and usual optimal weight coefficient rules are introduced briefly, some usual algorithms about adaptive digital beam forming are discussed and simulated in uniformity linear array (ULA).Secondly, the model of array signal processing is introduced and the common planar array pattern functions are derived. Adaptive nulls are formed at the pointing interfere direction by appending constrained conditions which are simulated by utilizing Minimum Variance Distortionless Response (MVDR) algorithm.Thirdly, the conception of conformal array is introduced and uniform conformal array patterns formula of cylindrical array, truncated conic array and hemispheric array are given. The number of array elements, the number of rings, ring spacing, tilt angle and the angle difference between rings to the impact of beamforming are analyzed.Finally, the algorithm of Sampling Matrix Inversion based on QR decompose (QRD-SMI) is introduced. Beamforming are simulated in ideal conditions on cylindrical array, truncated conic array and hemispheric array and adaptive nulls are formed at the pointing interfere direction by appending constrained conditions. And"shadow effect"is considered in beamforming of conformal array with directional elements and compared with ideal condition.