Study of Influence of Crossed Slot Geometry on Main Beam Direction

2021 ◽  
Author(s):  
Marija Milijic ◽  
Branka Jokanovic
Keyword(s):  
Main Beam ◽  
Beam Direction

scholarly journals Bioinspired DNA Origami Quasi-Yagi Helical Antenna with Beam Direction and Beamwidth Switching Capability

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Syed Imran Hussain Shah ◽  
Sungjoon Lim
Keyword(s):  
Dna Origami ◽  
Main Beam ◽  
Helical Chain ◽  
Beam Direction ◽  
Fixed Frequency ◽  
Helical Antenna ◽  
Dna Structures ◽  
Antenna Beam ◽  
Dna Molecule ◽  
Direction Switching

Abstract We propose a bioinspired origami quasi-Yagi helical antenna with beam direction and beamwidth switching capability based on transformable DNA origami structure. Each DNA molecule consists of a double helical chain, and its length can be transformed by folding and unfolding. When three transformable origami DNA structures are applied to the quasi-Yagi helical antenna, beam direction and beamwidth can be controlled by folding and unfolding the origami DNA. The transformable DNA structures act as driven, director and reflector elements. The proposed DNA origami antenna provides four beam direction switching states (three states with narrow beamwidth and one state with wide beamwidth) at fixed frequency of 1.9 GHz. For example, the main beam direction of the proposed antenna can be steered to −30°, 0°, +30° and −40° for states 1, 2, 3 and 4, respectively. State 4 provides a 3-dB wider beamwidth of 104°, whereas the beamwidth of other states is narrower than 64°. The proposed concept is numerically and experimentally demonstrated.

scholarly journals A Low-Profile High-Gain and Wideband Log-Periodic Meandered Dipole Array Antenna with a Cascaded Multi-Section Artificial Magnetic Conductor Structure

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4404 ◽  
Author(s):  
Son Trinh-Van ◽  
Oh Heon Kwon ◽  
Euntae Jung ◽  
Jinwoo Park ◽  
Byunggil Yu ◽  
...  
Keyword(s):  
High Gain ◽  
Operating Frequency ◽  
Main Beam ◽  
Impedance Bandwidth ◽  
Beam Direction ◽  
Magnetic Conductor ◽  
Artificial Magnetic Conductor ◽  
Low Profile ◽  
Operating Bandwidth ◽  
Meander Line

This paper presents a low-profile log-periodic meandered dipole array (LPMDA) antenna with wideband and high gain characteristics. The antenna consists of 14 dipole elements. For compactness, a meander line structure is applied to each dipole element to reduce its physical length. As a result, a compact and wideband LPMDA antenna is realized, exhibiting a wide impedance bandwidth of 1.04–5.22 GHz (ratio bandwidth of 5.02:1) for | S 11| < −10 dB. To enhance the antenna gain performance while maintaining the wideband behavior, the LPMDA antenna is integrated with a new design of an artificial magnetic conductor (AMC) structure. The designed AMC is realized by combining three AMC structures of different sizes to form a cascaded multi-section AMC structure, of which its overall operating bandwidth can continuously cover the entire impedance bandwidth of the LPMDA antenna. The proposed AMC-backed LPMDA antenna is experimentally verified and its measured −10 dB reflection bandwidth is found to be in the range of 0.84–5.15 GHz (6.13:1). At the main beam direction within the operating frequency bandwidth, the gain of the proposed AMC-backed LPMDA antenna ranges from 7.15–11.43 dBi, which is approximately 4 dBi higher than that of an LPMDA antenna without an AMC. Moreover, the proposed antenna has a low profile of only 0.138 λ L. ( λ L is the free-space wavelength at the lowest operating frequency).

scholarly journals Principle for the Realization of Dual-Orthogonal Linearly Polarized Antennas for UWB Technique

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Grzegorz Adamiuk ◽  
Mario Pauli ◽  
Thomas Zwick
Keyword(s):  
Substrate Surface ◽  
Single Point ◽  
Broad Band ◽  
Main Beam ◽  
Cross Polarization ◽  
Frequency Range ◽  
Beam Direction ◽  
Array Configuration ◽  
Uwb Radar ◽  
Linearly Polarized

A concept of an array configuration for an ultrawideband suppression of the cross-polarization is presented. The method is explained in detail, and a mathematical description of the principle is given. It is shown that the presented configuration is convenient for the development of very broad band, dual-orthogonal, linearly polarized antennas with high polarization purity. The investigated configuration shows a high decoupling of the orthogonal ports and is capable for antennas with a main beam direction perpendicular to the substrate surface, that is, for a planar design. The phase center of the antenna configuration remains fixed at one single point over the complete desired frequency range, allowing a minimum dispersion of the radiated signal. The influence of nonidealities in the feeding network on the polarization purity is investigated. The presented method introduces a superior possibility of an extension of typical UWB technique to fully polarized systems, which improves significantly performance in, for example, UWB-MIMO or UWB-Radar.

scholarly journals A Compact, Low-Profile Log-Periodic Meandered Dipole Array Antenna with an Artificial Magnetic Conductor

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Oh Heon Kwon ◽  
Sungwoo Lee ◽  
Jong Min Lee ◽  
Keum Cheol Hwang
Keyword(s):  
Ground Plane ◽  
Array Antenna ◽  
Main Beam ◽  
Beam Direction ◽  
Magnetic Conductor ◽  
Artificial Magnetic Conductor ◽  
Line Configuration ◽  
Low Profile ◽  
Unit Cells ◽  
Meander Line

A compact and low-profile log-periodic meandered dipole array (LPMDA) antenna with an artificial magnetic conductor (AMC) is proposed. For compactness, a meander line configuration is implemented with dipole elements and optimized using a genetic algorithm (GA) to realize the LPMDA antenna. As a result, a size reduction of approximately 30% is achieved as compared to a conventional log-periodic dipole array antenna. To enhance the gain characteristics, the AMC ground plane configuration is realized with 9 × 9 unit cells for the LPMDA antenna. Two prototypes of the proposed LPMDA antennas with and without an AMC are fabricated and measured to verify its performance. The measured −10 dB reflection ratio bandwidths are 2.56 : 1 (0.85–2.18 GHz) and 2.34 : 1 (0.92–2.16 GHz) for the proposed LPMDA antennas with and without the AMC, respectively. The gain at the main beam direction within the operating frequency bandwidth is significantly improved from 3.94–7.17 dBi to 7.86–10.01 dBi by applying the AMC.

scholarly journals GO Shaping of Omnidirectional Dual-Reflector Antennas with Arbitrary Main-Beam Direction in Elevation Plane by Connecting Conic Sections

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Rafael A. Penchel ◽  
Sandro R. Zang ◽  
José R. Bergmann ◽  
Fernando J. S. Moreira
Keyword(s):  
Method Of Moments ◽  
Phase Distribution ◽  
Main Beam ◽  
Hybrid Technique ◽  
Mode Matching ◽  
Conic Sections ◽  
Beam Direction ◽  
Reflector Antennas ◽  
Bodies Of Revolution ◽  
Shaping Procedure

This work discusses an alternative geometrical optics (GO) technique to synthesize omnidirectional dual-reflector antennas with uniform aperture phase distribution together with an arbitrary main-beam direction for the antenna radiation pattern. Sub- and main reflectors are bodies of revolution generated by shaped curves defined by local conic sections consecutively concatenated. The shaping formulation is derived for configurations like ADC (axis-displaced Cassegrain) and ADE (axis-displaced ellipse) omnidirectional antennas. As case studies, two configurations fed by a TEM coaxial horn are designed and analyzed by a hybrid technique based on mode matching and method of moments in order to validate the GO shaping procedure.

Properties of dual parabolic cylindrical reflectors

1985 ◽  
Vol 63 (10) ◽  
pp. 1299-1305 ◽  
Author(s):  
M. S. A. Sanad ◽  
L. Shafai
Keyword(s):  
Point Source ◽  
Optical System ◽  
Integration Method ◽  
The Other ◽  
Main Beam ◽  
Far Field ◽  
Beam Direction ◽  
System Parameters ◽  
Focal Line ◽  
Field Patterns

Two parabolic cylinders having the focal line of one coincident with the directrix of the other form an optical system that focuses the focal line of the first reflector to a point at infinity. The operation principle of such a system is studied, and its far diffracted field is determined. The unit is assumed to be illuminated by a directional point source, simulating a feed horn, and a ray-tracing approach is used to obtain the reflected and main diffracted fields over its aperture. The far-field patterns in the vicinity of the main beam direction are then computed by an aperture-integration method. The effects of various system parameters, on the far-field patterns, are also determined.

scholarly journals A 1-to-8 Fully Modular Stacked SIW Antenna Array for Millimeter-Wave Applications

2022 ◽  
Author(s):  
Cleofás Segura-Gómez ◽  
Ángel Palomares-Caballero ◽  
Pablo Padilla
Keyword(s):  
Antenna Array ◽  
Power Distribution ◽  
Main Beam ◽  
Impedance Bandwidth ◽  
Beam Direction ◽  
Array Design ◽  
Horn Antennas ◽  
Array Configuration ◽  
Minimum Number ◽  
Measured Impedance

This paper presents a vertically stacked SIW antenna array that enables different array configurations with the minimum number of SIW layers. This achievement lies in the modular feature offered by the proposed design. Specifically, 4 distinct array configurations can be produced with only 3 different design of SIW layers. Depending on the number of SIW layers employed in the stacked antenna, the directivity in the E-plane of radiation is modified. To obtain an equal and in-phase power distribution among the array elements, H- and E-plane corporate feeding networks are efficiently implemented in each array configuration. Array configurations of 1, 2, 4 and 8 radiating layers are offered by the proposed modular array, where each radiating layer is formed by 8 H-plane SIW horn antennas. The simulated directivity for the array configurations ranges from 15.8 dBi to 23.8 dBi and the main beam direction remains fixed along the operating frequency band. The array design has been manufactured and proper agreement between simulated and measured results are observed. The measured impedance bandwidth in all the array configurations is from 35 GHz to 41 GHz (15.79% bandwidth) with a reduction in the E-plane beamwidth as the number of radiating layers increases.

Design of a compact high gain printed octagonal array of spiral-based fractal antennas for DBS application

2020 ◽  
Vol 12 (8) ◽  
pp. 769-781
Author(s):  
Kalyan Sundar Kola ◽  
Anirban Chatterjee ◽  
Deven Patanvariya
Keyword(s):  
High Gain ◽  
Main Beam ◽  
Single Element ◽  
Patch Antennas ◽  
Cross Polarization ◽  
Beam Direction ◽  
Microstrip Patch Antennas ◽  
Spiral Geometry ◽  
Feed Network ◽  
Direct Broadcast Satellite

AbstractThis paper presents a compact octagonal array of microstrip patch antennas for direct broadcast satellite (DBS) (12.2–12.7 GHz) services. The proposed single element of this array is a new fractal antenna, having considerably high gain and can heavily suppress cross polarization along the main beam direction. The single element is derived from a 2D spiral geometry. The corporate feed network of the array is designed in such a manner to make the structure very compact. The fabricated single element resonates at 12.51 GHz and gives a gain and bandwidth of 9.32 dBi and 280 MHz, respectively. The array resonates at 12.46 GHz and gives gain of 17.67 dBi and a bandwidth of 506 MHz, which ensures a 100% coverage of the entire DBS service band. The measured cross polarization of single element and array along the direction of main beam are −45.50 and −43.35 dB, respectively. Both the single element as well as the array maintains a reasonably good radiation efficiency of 86.70 and 82.20%, respectively.

scholarly journals A Modified Vivaldi Antenna for Improved Angular-Dependent Fidelity Property

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Zhi Zeng ◽  
Ke Xu ◽  
Zhaohui Song ◽  
Qinyu Zhang
Keyword(s):  
Half Space ◽  
Time Domain ◽  
Spatial Filter ◽  
Main Beam ◽  
Experimental Measurements ◽  
Beam Direction ◽  
Analysis Design ◽  
Vivaldi Antenna ◽  
Better Than

The analysis, design, and realization of a modified Vivaldi antenna optimized for time domain fidelity factor in the half-space located in the direction of the antenna main beam are presented. The proposed antenna shows improved angular-dependent fidelity property, with respect to the signal transmitted in the main beam direction. A substantial increase in the fidelity factor is achieved by utilizing spatial filter effect introduced by adding two dielectric slabs parallel to the antenna substrate. By choosing optimal dimensions and location of the slabs, the signal waveforms in the mentioned half-space are equalized so as to improve the quality of the radiated signal waveform in the main beam direction. As a result, the fidelity property in the half-space is improved greatly. The simulated and measured fidelity factor in the angular operational region is studied and compared with experimental measurements. The ranges with the fidelity factor better than the value of 0.9 are improved by 95% in H-plane and by 14% in E-plane, respectively.

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