Current Issue : April-June Volume : 2023 Issue Number : 2 Articles : 5 Articles
In this paper, a new beamforming algorithm for phased array antennas is proposed, the plant growth gene algorithm. The algorithm consists of three steps. Firstly, according to the excitation relation of the array unit before and after the local fine-tuning of the antenna radiation pattern, the model for solving the array unit excitation difference is established. Secondly, the Taylor series expansion is used to solve the model, and the growth model is established based on this, and the beam tuning network is designed to realize the growth model. Finally, based on the growth gene obtained by the neural network algorithm, the growth model is called multiple times for high-precision beamforming. This algorithm converts the complex optimization process of array antenna excitation by the classical optimization algorithm into a simple process of fine-tuning the gain at any angle on the beam to make it grow and approach the target pattern. The growth gene is used to weigh the target angle and gain to achieve beamforming, which greatly reduces the complexity of the algorithm and improves its accuracy of the algorithm. Taking a 1 × 16 linear array as an example, a cosecant square beam pattern with a coverage range of −31° to 31° and a maximum gain direction of 17° is designed using the algorithm proposed in this paper. The experimental results show that the proposed algorithm can easily fine-tune the gain of any angle to achieve precise beamforming. Importantly, the growth genes trained by the algorithm are universal to the phased array antenna with the same topology....
A wideband circularly polarized rectangular dielectric resonator antenna (DRA) fed by a single feeding mechanism has been studied theoretically and experimentally. The purpose of the study is to determine how adding a parasitic strip next to the flat surface metallic feed would affect various far‐ and near‐field antenna characteristics. Initially, the basic antenna design, i.e., the Tshape feed known as antenna A, produced a 4.81% impedance matching bandwidth (|S11| −10 dB). Due to the narrow and undesirable results of the initial antenna design, antenna‐A was updated to the antenna‐B design, i.e., Yagi‐Uda. The antenna‐B produced a decent result (7.89% S11) as compared to antenna‐A but still needed the bandwidth widened, for this, a parasitic patch was introduced next to the Yagi‐Uda antenna on the rectangular DRA at an optimized location to further improve the results. This arrangement produced circular polarization (CP) waves spanning a broad bandwidth of 28.21% (3.59–3.44 GHz) and a broad impedance |S11| bandwidth of around 29.74% (3.71–3.62 GHz). These findings show that, in addition to producing CP, parasite patches also cause the return loss to rise by a factor of almost three times when compared to results obtained with the Yagi‐Uda‐shape feed alone. Computer simulation technology was used for the simulation (CST‐ 2017). The planned antenna geometry prototype was fabricated and measured. Performance indicators show that the suggested antenna is a good fit for 5G applications. The simulated outcomes and measurements match up reasonably....
This paper presents a circularly polarized (CP) multiple-input multiple-output (MIMO) antenna using a microstrip patch and parasitic elements. The proposed design exhibits wideband characteristics for both impedance and axial ratio bandwidths. Especially, the mutual coupling between the MIMO elements is significantly depressed without using any decoupling network. To achieve these features, parasitic elements are positioned nearby and in different layers to the radiating elements. The measured results demonstrate that the proposed MIMO CP antenna has a wideband operation of 11.3% (5.0–5.6 GHz), which is defined by an overlap between −10–dB impedance and 3–dB axial ratio bandwidths. Across this band, the realized gain is better than 6.0 dBi, and the isolation is greater than 32 dB with the highest value of 45 dB. The MIMO parameters such as the envelope correlation coefficient, diversity gain, and channel capacity loss are also investigated thoroughly, which are found to be good on the scale of diversity standards....
In this paper, a Millimeter Wave antenna is designed which has a compact, lightweight and planar configuration. The frequency band is 27–29.5 GHz as a candidate band for 5G/millimeter Wave (mmW) systems. The antenna structure is similar to Quasi Yagi antenna which has driver, director, feeding part, and reflector. Substrate Integrated Waveguide used for feeding part of single element antenna and Wilkinson power divider used for antenna array feeding network. Theproposed antenna has been simulated, fabricated, and measured (S11, E, and H pattern). The simulation and measurement values showed good similarity. The switched line phase shifter used to consider the beam steering (rotation) ability of the designed antenna which is important in (mmW) systems such as RADARs and mobile handsets. To evaluate this ability, for 0°, 30°, 45°, and 90° phase differences, the beam steering angle (θ) simulated and also for −90° and 90° implemented. The results showed that the efficiency, S11, and E patterns in the rotated beam is suitable and without degradation in antenna operation. To simulate and evaluate the designed antenna HFSS and CST Software are used....
This article presents a reconfigurable antenna using digitally tuneable capacitors (DTCs). Mounted on a 120 × 200 mm2 ground plane, the radiating element has very compact dimensions of 0.06λg × 0.016λg × 0.0016λg (with λg being the wavelength at 585 MHz). The proposed structure could be operated in the white-space frequency band from 470 to 700 MHz. The antenna system is composed of two radiated elements that are placed at the corner of the board. The active components were soldered onto the antennas and controlled by an embedded microcontroller via the I2C interface. Antenna impedances were simulated and evaluated by measurement with an impedance-matching bandwidth of 39.32% (470–700 MHz) for an S11 less than −6 dB. Furthermore, the numerical results show a realized maximal gain ranging from −2.2 dBi at 470 MHz to 1.87 dBi at 700 MHz. Lastly, the diversity gains based on the radiation pattern of two resonators were calculated. The results show envelope correlation coefficient (ECC) values lower than 0.5 for the different configurations....
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