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With the development of multifunctional satellites, the integration and multiplexing of satellite resources become increasingly important. Large-scale radio-frequency microelectromechanical system (RF MEMS) switch matrix technology is one of the key technologies to design a multifunctional satellite. This study proposed a novel sequential rotation crossbar (SRCrossbar) topology for large-scale RF MEMS switch matrices. A specifically designed novel configuration scheme or arraying method for SR-Crossbar topology is also proposed. The number of switch elements in the SR-Crossbar RF MEMS switch matrix is significantly reduced; hence, the reliability and performance of the matrix can be improved simultaneously. For an N × N RF MEMS switch matrix, in a fully configured scenario, the maximum number of switch elements in all the paths are N(N + 1)/2. When N ≥ 4, the proposed SR-Crossbar RF MEMS switch matrix topology is better than the planar Benes topology, which is already an optimised planar switch matrix topology with the minimum number of nodes.

A fast adaptive interference nulling algorithm with arbitrary pattern maintaining without direction of arrival is proposed under the framework of generalised sidelobe canceller (GSC). The problem is formulated to optimise the weight by minimising the total output power of the beamformer, while keeping the antenna gain accurately approximated to that of the quiescent pattern by the mainlobe subspace constraint (MSC) and the weight quadratic constraint. The MSC is constructed by the dominant eigenvectors of the mainlobe covariance matrix. The closed-form solution to this problem is obtained by two steps. First, the quadratic constraint is relaxed to obtain the weight in the form of a GSC beamformer with diagonal loading (DL) sample covariance matrix. Then, the stringent quadratic constraint is guaranteed by optimising the DL level, which is precisely estimated by a simple iterative equation. The maintenance of pattern mainlobe and the reduction of the computation complexity can be achieved simultaneously. Numerical experiments are performed to demonstrate the effectiveness and efficiency of the proposed algorithm, and discuss the influence of mutual coupling between antenna elements.

A new synthesis algorithm for arbitrarily shaped patterns generated by transmitting and receiving arrays is proposed in this study. First, according to the radar range equation, the authors vividly present the definition of the joint pattern of the transceiving array. To solve the joint optimisation problem, the projectors over pattern and excitation constraints are provided based on alternating projection method. In many traditional methods, the excitations are obtained by solving the (weighted) least mean squares (WLMS) problem. Nevertheless, in this study, WLMS problem is rewritten as a constrained WLMS problem, which introduces an effective proximal splitting method to improve the convergence and stability. Besides, to make full use of transmitting module, the excitation dynamics of transmitting array is enforced to be 0 dB. To validate the good applicability of the proposed method, two arrays in different shapes are applied. Five examples with embedded patterns including phase-only synthesis, pattern with unbalanced sidelobe levels etc., are presented to highlight the various aspects of the method. In general, the new method not only can restrict the pattern shape, also can constrain the excitations of transmitting and receiving arrays, respectively.