Abstract
This paper discusses how to optimize the weighting of individual subarrays to derive the low sidelobe level (SLL) based on quadratic programming (QP) and how to derive QP parameters to ensure that the objective function is composed of the quadratic function form, with the actual number identical to the standard objective function of QP. Next, in order to analyze the SLL, a 24 × 24 phased array antenna was compared with 96 transmit–receive modules (TRMs) attached only to the subarray stage and a phased array antenna with 576 TRMs attached to all radiating elements without a subarray. Optimized weighting was applied to the array antennas with a subarray, and Taylor weighting was applied to the array antennas without a subarray. The number of TRMs used in the phased array antenna with the optimized weighting was reduced by 83.3% compared to the phased array antenna in which TRMs were attached to all radiating elements. The SLL and the half-power beamwidths (HPBWs) of the two antennas were practically identical in a narrow beam-scanning environment. Finally, an array pattern (AP) in which mutual coupling between the radiating elements was considered was calculated to verify the optimized weighting. Moreover, the optimized weighting was applied to CST Microwave Studio (an EM full-wave simulation) to compare the results from the AP calculation and a simulation. It was confirmed that the two results above are largely indistinguishable. The analysis found that the HPBW is 3.6∘ × 3.6∘ and the SLL is −26.18 dB from AP calculations in the boresight direction. When each 5∘ beam was scanned at the azimuth and elevation, the corresponding HPBW values were 3.7∘ × 3.7∘ and 3.7∘ × 3.7∘ and the SLLs were −22.70 dB and −24.44 dB according to the AP calculations.
Highlights
An active phased array antenna is composed of hundreds or thousands of radiating elements
We introduce a method by which to optimize the weighting of each subarray based on quadratic programming (QP) to acquire a low sidelobe level (SLL)
The AF was transformed into a quadratic function composed of real numbers to apply QP to the array environment, and QP parameters were derived so that the AF could conform to the QP objective function
Summary
An active phased array antenna is composed of hundreds or thousands of radiating elements. A radiation pattern with a low SLL was obtained by optimizing the shape of the subarray and the weighting applied to each subarray utilizing an excitation matching method [14]. In order to implement the phased array antenna system applied to the subarray as shown, the excitation amplitude and phase of the radiating elements belonging to the same subarray must be equal. The phase center of the subarray is determined by the position of the radiating element in the subarray and the applied weighting through Equation (4) [23]. Before weighting optimization, the subarray shape was optimized into 96 subarrays by GSO of a rectangular lattice array (24 × 24) antenna initially with 576 radiating elements. Using Equation (1) as a cost function of GSO, the subarray shape was optimized to avoid grating lobes when scanning on the condition of uniform weighting. The weighting optimization method by QP on the optimized subarray shape, which is an aperiodic environment, is introduced
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
