Analysis of a Three - Quarter Wavelength Antenna Array for UHF Satellite Communication Band

The Design and Implementation of a Phased Antenna Array System for LEO Satellite Communications

“…The three-quarter wavelength (3λ/4) antenna element offers several advantages that will be highlighted in the following paragraphs. Different studies [ 23 , 24 , 25 , 26 ] revealed that compared to other antenna configurations, such as half-wavelength (λ/2) and the widely used quarter-wavelength (λ/4), in the case of the 3λ/4 antenna element, in the radiation pattern’s vertical plane, the maximum radiation lobe (main lobe) rises towards medium elevation angles, while preserving its omnidirectional characteristic in the horizontal plane. Additionally, even at low elevation angles, the 3λ/4 antenna gain is superior to, or at least equal to, that offered by the widely used conventional λ/4 vertical monopole elements, but also to that provided by the λ/2 configuration.…”

“…Due to mutual coupling effects between array elements [ 12 , 34 ], it is expected that the resonant frequency of the system of four antennas will be greater than that of a single element tunned on the same frequency and have the same length. Previous research [ 26 ] showed that in practice, for tuning a two-element three-quarter wavelength antenna array to the resonant frequency close to 434 MHz, each individual element needed to be dimensioned for 426 MHz (about 8 MHz lower) resonance. Then, after implementation into the two-element antenna system, fine-tuning of the elements was initiated while keeping the same length corresponding to 426 MHz.…”

“…A module for controlling the shape and direction of the antenna array radiation pattern (also generally known as a beamforming module [ 12 , 26 , 33 ]) was designed and implemented and consists of a splitter/combiner, phase shifters, basic PCB and microprocessor-based control module. In the phased antenna array presented in this article, we have successfully integrated the original concept together with previously developed phase shifters that have already been tested for linear antenna arrays.…”

“…A module for controlling the shape and direction of the antenna array radiation pattern (also generally known as a beamforming module [12,26,33]) was designed and implemented and consists of a splitter/combiner, phase shifters, basic PCB and microproces- The phase shifters are denoted with PS1-PS4, and the corresponding phase shifts are introduced with W 1 -W 4 . All components were electromagnetically shielded and electrically connected to the ground plane.…”

“…The high-performance Teensy 4.0 development module included an ARM Cortex-M7 at 600 MHz microcontroller with the possibility of overclocking up to 1 GHz, float point math unit-64 and 32 bits, 1984K Flash, 1024K RAM, USB device 480 Mbit/sec and USB host 480 Mbit/sec was used for controlling the phased antenna array's main radiation lobe orientation in the azimuth plane. As shown in Section 4, the data regarding the satellite azimuth angle can be imported from Orbitron software, the phase shift values (w1, w2, w3, w4) given by ( 10)-( 13) and A module for controlling the shape and direction of the antenna array radiation pattern (also generally known as a beamforming module [12,26,33]) was designed and implemented and consists of a splitter/combiner, phase shifters, basic PCB and microprocessor-based control module. In the phased antenna array presented in this article, we have successfully integrated the original concept together with previously developed phase shifters that have already been tested for linear antenna arrays.…”