Synthesis of Rotated Sparse Linear Dipole Array with Shaped Power Pattern

© 2018 ACES. A new shaped pattern synthesis method is presented in which element rotations, positions and phases are co-optimized to produce a shaped beam pattern for a sparse dipole array. Compared with conventional shaped pattern synthesis using excitation amplitude and phase optimization, the proposed method can not only reduce the number of elements But also avoid the usage of unequal power dividers. A synthesis example is provided to verify the performance of the proposed method

Electronic Control Board for Phased Antenna Array Research and Prototyping

Czech Science Foundation under the project number 20-02046S (Antenna Arrays with Quantized Controlling)Current state-of-the-art phased antenna arrays used in modern generations of mobile networks and radars in terrestrial applications or as spacecraft antennas in space applications tend to be very complex and expensive devices with many mutually coupled elements and many input/output ports that are excited with varying amplitude and phase. Also, the simulation and design of such complex antenna arrays may not be accurate due to many sources of uncertainty, such as inhomogeneity of high-frequency substrate properties over large area, manufacturing tolerances, idealized component models, etc. Therefore, simpler solutions of these antenna arrays in the form of sparse arrays, non-uniform arrays or arrays with parasitic elements are intensively studied. In this paper, we present an experimental electronic control board, which is used in our research of simplified phased array antennas. This digitally controllable board, in addition to the commonly used changes in the amplitude and phase of the propagated signal, can connect the individual antenna elements to a programmable impedance load, variable in the capacitive and inductive range. The aim of the implementation of this control electronic board is to study the influence of the mutual couplings of actively excited elements of the antenna array and parasitic elements loaded by variable impedance load on the resulting properties of the antenna array

Adaptive Sparse Array Beamformer Design by Regularized Complementary Antenna Switching

In this work, we propose a novel strategy of adaptive sparse array beamformer design, referred to as regularized complementary antenna switching (RCAS), to swiftly adapt both array configuration and excitation weights in accordance to the dynamic environment for enhancing interference suppression. In order to achieve an implementable design of array reconfiguration, the RCAS is conducted in the framework of regularized antenna switching, whereby the full array aperture is collectively divided into separate groups and only one antenna in each group is switched on to connect with the processing channel. A set of deterministic complementary sparse arrays with good quiescent beampatterns is first designed by RCAS and full array data is collected by switching among them while maintaining resilient interference suppression. Subsequently, adaptive sparse array tailored for the specific environment is calculated and reconfigured based on the information extracted from the full array data. The RCAS is devised as an exclusive cardinality-constrained optimization, which is reformulated by introducing an auxiliary variable combined with a piece-wise linear function to approximate the $l_0$-norm function. A regularization formulation is proposed to solve the problem iteratively and eliminate the requirement of feasible initial search point. A rigorous theoretical analysis is conducted, which proves that the proposed algorithm is essentially an equivalent transformation of the original cardinality-constrained optimization. Simulation results validate the effectiveness of the proposed RCAS strategy

Receive mode time modulated antenna array incorporating subsampling -theoretical concept and laboratory investigation

An eight element Subsampling Time Modulated Array (STMA) operating in receive mode with a carrier at 2.4 GHz is presented and demonstrated using bespoke Radio Frequency (RF) hardware. Each STMA cell incorporates subsampling functionality, with the sampling frequency significantly below the carrier frequency and requiring minimal additional hardware. By using this concept, the hardware required for a receiver incorporating an antenna array can be reduced and costs saved. STMA design equations and architecture strategies are presented, and a prototype hardware demonstrator is introduced. Laboratory measurements confirm that a received radiated signal, arranged to use the fundamental or a harmonic beam pointed at the radiating source, can be resolved from the subsampled intermediate frequency (IF) output. The concept demonstration hardware provides a measured array conversion gain of 11.4 dBi on the boresight beam, 7.8 dBi on the first positive and 11.3 dBi on the first negative harmonic beams, as resolved at the final combined IF output. The array IF output Signal to Noise and Distortion ratio is 69 dB. The dependence of array sidelobe level performance on STMA sampling switch rise time is also uncovered, though good performance with real, imperfect, hardware is still obtained