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In this article, we consider the problem of beampattern synthesis with sidelobe control using constant modulus weights. We specifically focus on two applications, i.e., notching and sidelobe-level (SLL) control (SLC). The considered problem is a challenging NP-hard due to the employed constant-modulus weights. Here, we convert the problem into an intermediate form by incorporating auxiliary variables and changing the form of the constant modulus. Then, we decompose the intermediate form into subproblems of single constraint each. Finally, we propose an iterative solution following the alternate direction method of multipliers (ADMM) and Proximal frameworks. The proposed solution solves the original problem by iteratively solving the subproblems in coordinated logical order. Importantly, it combines the convergence speed of ADMM and convergence property of Proximal methods. In addition, it always satisfies the constant modulus constraint. The solution has a significant contribution to mitigate interference using notching and to realize RadCom. Simulation results show that the proposed solution has a better performance in terms of computational speed, notching, and constant SLL than the previous works. [ABSTRACT FROM AUTHOR]

The design and nulling capability of a compact 2 \times 2 dual-band coupled double loop (CDL) GPS antenna array loaded with broadside coupled split ring resonators (BC-SRR) are presented. The high level of L2 band mutual coupling is reduced by utilizing \mu-negative (MNG) BC-SRR metamaterial within the array volume. This metamaterial loading is possible due to the small L2 band electrical size (\lambda0/8.5\times\lambda0/8.5) of the CDL antenna elements. Different than the existing work on coupling reduction of linearly polarized antenna arrays, mutual coupling mechanism within the circularly polarized GPS array is considered and MNG metamaterials are shown to reduce the mutual coupling if they are placed between the antennas in a particular alignment. Specifically, a 2 \times 2 array with \lambda0/3.7 inter-element spacing is designed to be loaded with BC-SRRs and experimentally verified to exhibit a 10 dB L2 band mutual coupling reduction. Through simulations and experiments, it is also demonstrated that the reduction in L2 band mutual coupling improves the L2 band array nulling capability in terms of accuracy and null depth without affecting the already well-behaved L1 band performance. The presented array has an overall footprint size of 4.3^\prime\prime\times 4.3^\prime\prime and can be potentially miniaturized further for different inter-element spacing. [ABSTRACT FROM PUBLISHER]