Transmitarray Using Perforated Dielectric Material for Wideband Applications (original) (raw)

Perforated Dielectric Resonator Antenna Reflectarray

2011

A wideband perforated rectangular dielectric resonator antenna (RDRA) reflectarray is presented. The array of RDRA are formed from one piece of material. Air-filled holes are drilled into the material around the RDRA. This technique of fabricating RDRA reflectarray using perforations eliminates the need to position and bond individual elements in the reflectarray and makes the fabrication of the RDRA reflectarray feasible. The ground plane below the reflectarray elements is folded to form a central rectangular concave dip so that an air-gap is formed between the RDRA elements and the ground plane in order to increase the bandwidth. Full-wave analysis using the finite integration technique is applied. Three cases are studied. In the first one, the horn antenna is placed at the focal point to illuminate the reflectarray and the main beam is in the broadside direction. In the second one, the horn antenna is placed at the focal point and the main beam is at ±30 degrees off broadside direction. In the third one, an offset feed RDRA reflectarray is considered. A variable length RDRA provides the required phase shift at each cell on the reflectarray surface. The normalized gain patterns, the frequency bandwidth, and the aperture efficiency for the above cases are calculated.

Wideband perforated rectangular dielectric resonator antenna reflectarray

2011 IEEE International Symposium on Antennas and Propagation (APSURSI), 2011

Transmitarray Antenna Design Using Cross-Slot Elements With No Dielectric Substrate

IEEE Antennas and Wireless Propagation Letters, 2014

The transmitarray antenna has received considerable attention in recent years as it combines the favorable features of the lens antenna and the array techniques. The goal of this letter is to present detailed design analysis of a multiple-conductor-layers transmitarray antenna using slot-type element with no dielectric substrate. A transmitarray antenna using quad-layer cross-slot elements has been designed, fabricated, and tested for 11.3 GHz operating frequency. The measured gain of the prototype transmitarray is 23.76 dB at 11.3 GHz. It is observed that the oblique incidence and the wave polarization have strong effect on the transmission coefficient of the slot-type element. Thus, a detailed analysis of the transmitarray considering the oblique incidence angles and the feed polarization conditions is performed with good agreement between the simulation and measured results.

Linearly Polarized Transmit-array Operating in mmWave Bands, Design, Optimization and Demonstration

2022 16th European Conference on Antennas and Propagation (EuCAP)

This paper presents the design and optimization of a transmit-array (TA) operating at 10 GHz. This TA is based on a new unit-cell that allows to generate an easy phase rotation required for TA design, while keeping insertion losses to a minimum. The proposed unit-cell is a simple three metallic layer structure, in which two identical square patches are interconnected through an inner via. The optimized structure has a low profile with a total thickness of only 3.2 mm (0.1λ0), the simple design allows standard and low cost PCB printing. The unitcell is designed with CST Microwave Studio and measured with a waveguide measurement system for S-parameters validation. The results show a working bandwidth of 900 MHz (9% relative bandwidth) and insertion losses of 0.3 dB at 10 GHz, full wave simulations show an unit-cell gain of 4.8 dBi making it a very suitable choice for TA design. To demonstrate its performance, a 1-bit transmit-array with 20×20 cells is proposed, simulated and manufactured showing a high gain of 21.01 dBi and low side lobe levels (-20.93 dB). Finally, to reduce the overall profile of the TA, a multiple feed TA is conceived using an particle swarm optimization (PSO) algorithm to define the phase compensation distribution and allows a reduction of 50% of the focal length.

3D-Printable Dielectric Transmitarray With Enhanced Bandwidth at Millimeter-Waves

IEEE Access, 2018

In this paper, a three-layer dielectric structure is presented as innovative unit-cell element for transmitarray (TA) antennas with enhanced bandwidth. It consists of a central layer, with a varying size square hole, used to compensate the phase of the incident field and located between two other identical layers with linearly tapered square holes, acting as matching circuits. The effectiveness of this unit-cell is demonstrated by the numerical and the experimental results here presented. As a first step, three different TAs with increasing size are designed and simulated: their 1-dB gain bandwidth, centered at 30 GHz, varies from the 30.9% of the smallest configuration, having size of 10λ 0 × 10λ 0 , to the 17.5% of the 20λ 0 × 20λ 0 TA. A slightly modified unit-cell is then designed, with the aim of realizing a prototype with an additive manufacturing (AM) technique. A 3D-printed dielectric TA with a size of 15.6λ 0 × 15.6λ 0 has been manufactured and experimentally characterized. The measured prototype shows excellent performances, achieving a 1-dB gain bandwidth of 21.5%: these results prove the enhanced features of the introduced unit-cell and demonstrate the TA feasibility with AM techniques. INDEX TERMS Wideband antenna, transmitarray antenna, planar lens, discrete lens, tapered matching, 3D-printed antenna, 3D-printing.

Design of a Transmitarray Antenna Using 4 Layers of Double Square Ring Elements

Progress In Electromagnetics Research Letters, 2020

Conventional dielectric lenses rely on the accumulation of phase delay during wave propagation to produce a desired wavefront. By considering the required phase delay at each lens position, an 'equivalent' transmitarray antenna can be obtained. Despite a lack of curvature as in conventional lenses, the phase delay in the transmitarray antenna is achieved via a periodic arrangement of unit cell elements to bend the incident waves in the desired directions. This paper presents the design and characterization of a 4-layer transmitarray antenna consisting of double square ring elements. The gap between the double square rings is varied as a fixed proportion of their dimensions, while keeping the widths constant. The transmitarray element can achieve a transmission phase range of 235 • with a loss of less than 3 dB. The performance of the transmitarray antenna is explicitly compared to that of a convex dielectric lens, both of which are operating at 8 GHz.

Transmitarray Antenna Based on Parallel-plate Transmission Line with HighEfficiency and Large Gain Bandwidth

IET Microwaves, Antennas & Propagation, 2019

A dual-polarised transmitarray antenna unit cell based on conventional parallel-plate with low loss and wide bandwidth is proposed. A conventional parallel-plate is developed into two new structures; the first structure consists of two sets of parallel-plates forming a four-wall transmission line, while in the second structure the plates of the first structure are replaced by sets of strips. To ease the fabrication, in both cases, the plates are etched on FR4 substrates. These two structures are evaluated as the unit cell of transmitarray antenna to improve the efficiency and gain bandwidth. There is a basic difference between these two unit cells: the first unit cell increases the phase velocity and the second unit cell reduces the phase velocity while passing through the unit cells. Therefore, the layout of the metal antenna plates designed based on the first unit cell becomes concave-like and the layout of the metal antenna plates designed based on the second unit cell becomes convex-like. The antenna designed based on the second unit cell results in higher efficiency as such this antenna is fabricated and measured. The measured results show that the antenna has a peak efficiency of 85.6% and 1 dB gain bandwidth of 22.6%.

Designing Wideband Microstrip Reflectarrays for 10 GHz

European Journal of Science and Technology, 2022

This paper presents two microstrip reflectarray designs based on variable size unit cells for 10 GHz. One design uses a 3-layer unit cell with polygon shaped patch and the other uses a unit cell with 1-layer square loop patch. Both arrays have a size of 10λ × 10λ at 10 GHz, can reflect the incoming wave as a high gain pencil beam in the desired direction of θ = 30°. Gains at 10 GHz are 23.6 dB and 26.1 dB for the 3-layer and one-layer structures, respectively. The multi-layer structure resulted in a wider gain banwdith. Simulation results show that the 3-dB gain bandwdith is about 22% for the 3-layer structure reflectarray, as compared to 12% for the one-layer structure.

Bandwidth Improvement Methods of Transmitarray Antennas

IEEE Transactions on Antennas and Propagation, 2015

Despite several advantages of planar transmitarray antennas compared to conventional lens antennas, they have a narrow bandwidth. The goal of this paper is to improve the bandwidth of transmitarray antennas through the control of the transmission phase range and the optimization of the phase distribution on the transmitarray aperture. To validate the proposed approaches, two quad-layer transmitarrays using double square loop elements have been designed, fabricated, and tested at Ku-band. The transmission phase distribution is optimized for both antennas, while they differ only in the transmission phase ranges. It is shown that the transmitarray antennas designed using the proposed techniques achieve 1-dB gain bandwidth of 9.8% and 11.7%, respectively. The measured gains at 13.5 GHz are 30.22 dB and 29.95 dB, respectively, leading to aperture efficiencies of 50 % and 47 %, respectively.

Wideband Transmitarray With Reduced Profile

IEEE Antennas and Wireless Propagation Letters, 2018

This letter presents a wideband transmitarray (TA) with reduced profile. A novel unit cell based on a wideband bandpass filter is developed and applied to the design of the TA. The TA consists of two identical trilayer frequency selective surfaces (FSSs), thus it has a lower profile compared to traditional designs that use at least four FSS layers separated by quarter-wavelength air gaps to obtain the 360 • phase shift range. The FSS has a pair of square patches printed on the top and bottom layers, and a square slot loaded by four microstrip lines printed on the middle layer. The phase shift is achieved by simultaneously adjusting the size of the square patches. Within the frequency band of interest, the developed unit cell shows low insertion loss and sufficient phase shift range. An equivalent circuit model is developed to better understand the operating principles of the FSS. To validate the design concept, one prototype operating at 13.5 GHz is designed, fabricated, and measured. The measurement results show that the designed TA achieves 16% 1 dB gain bandwidth and 60% aperture efficiency. The developed unit cell has symmetric configurations so it can also be applied to the design of dual-polarized or circularly polarized TAs.

Transmitarray Using Perforated Dielectric Material for Wideband Applications (original) (raw)

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