• Journal of electromagnetic engineering and science
• /
• v.18 no.3
• /
• pp.182-187
• /
• 2018

A low profile asymmetrical fractal boundary patch antenna based on reactive impedance surface (RIS) and a mushroom unit cell (MUC) is proposed and studied for dual band operation. The sides of the square patch antenna are replaced with asymmetrical half circled fractal curves for circular polarization operation at patch mode band. The fractal patch antenna is loaded with MUC for dual band operation. The antenna radiation characteristics are investigated and illustrated with both simulated and experimental results in detail. The 10-dB return loss bandwidth are 8.48% (3.21-3.49 GHz) and 2.59% (2.30-2.36 GHz) at upper and lower resonance frequencies, respectively. The 3-dB axial ratio bandwidth is 4.26% (3.21-3.35 GHz). A close agreement between simulation data with experimental results is observed.

• Journal of Astronomy and Space Sciences
• /
• v.26 no.3
• /
• pp.345-354
• /
• 2009

A stepped septum polarizer has been designed and fabricated for the 43 GHz band KVN receiver system. The dual-circular polarizer converts left and right hand circularly polarized signals into linear polarizations in two separated rectangular waveguides. Measurements show that the performance of the designed septum polarizer covering 42-48 GHz frequency band is adequate to meet the requirement of KVN receivers. Especially, a polarizer for the KVN receiver of 85-95 GHz frequency band can be fabricated by scaling the dimensions of the septum polarizer developed in this paper.

• Journal of the Microelectronics and Packaging Society
• /
• v.28 no.3
• /
• pp.25-32
• /
• 2021

In this paper, the Magneto-Electric(ME) dipole array antenna with dual-polarization in the X-Band is proposed and it is implemented and measured. The proposed array antenna is composed of 32 single ME dipole antenna and a Teflon PCB. 1 × 1 ME dipole antenna is implemented dual-polarization by radiating vertical polarization and horizontal polarization from two pairs of radiators. 2-port feeding structures are realized by lamination process using LTCC. And, each port independently feeds the radiator through a Γ-shaped feeding strip with isolation between ports. The Teflon PCB used in the antenna array has a 4-layer structure, and 2-port is fed through the top and bottom layers. The λ_g/4 transformer is applied to the transmission line of the Teflon PCB for impedance matching of the arrayed antenna and the Teflon PCB, and the optimal parameters are obtained through simulation. The measured maximum antenna gains of port 1 was 18.2 dBi, Cross-pol was 1.0 dBi. And the measured maximum antenna gains of port 1 was 18.1 dBi, Cross-pol was 3.2 dBi.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.11 no.3
• /
• pp.138-145
• /
• 2008

In this paper, the waveguide slot array antenna which is capable of wide beam steering and dual polarization is designed for an X band synthetic aperture radar. In order to improve the restriction of beam steering range and to remove the butterfly lobes, a typical waveguide slot array antenna has been modified. To implement dual polarization, rod excited waveguide slot elements and ridge waveguide slot elements are alternately arranged. Location of slots, inclination of rod and offset distance of slots are determined on using array characteristic and conductance constant with radiating power on slots. The designed antenna is manufactured and measured with Near-filed measurement method.

• Journal of the Institute of Convergence Signal Processing
• /
• v.16 no.4
• /
• pp.156-161
• /
• 2015

In this paper, a dual-polarized multi-band multi-layer antenna for a vehicle, which operates in the GPS, bluetooth, and DSRC bands, was implemented. The antenna was designed as a multi-layer structure, and a FR4-epoxy substrate with =4.4 and =1.6mm was used. GPS and DSRC antennas have circular polarized characteristics, and a single probe feeding method was applied. Simulated results by Ansys HFSS v11 was compared with the measured ones. The size of the optimally designed antenna is $67mm{\times}67mm{\times}4.8mm$, -10dB bandwidth of the anatenna was measured to be 820MHz, 127MHz, and 862MHz in each band, and 3dB AR bandwidth of the antenna was simulated to be 19MHz and 110MHz in GPS and DSRC bands. The results confirmed that suggested system satisfies the system requirements.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.715-718
• /
• 2002

TX/RX dual microstrip 1$\times$8 sub-array antennas are designed, fabricated, and measured for a wideband array antennas in communications. They have a Right Handed Circular Polarization (RHCP) for TX from 7.9 to 8.4 GHz and Left Handed Circular Polarization (LHCP) for RX from 7.25 to 7.75 GHz. Two stacked patches are used for a wideband characteristics and cornertruncated square patches are adopted for a circular polarization. To enhance bandwidth characteristics of a circular polarization, 1$\times$2 sequential rotation arrays are applied. From the measured results, 1$\times$8 microstrip sub-array antennas have a good agreement with those of the simulation. Therefore the sub-array antennas are applicable to satellite communication antennas, active phased array antennas, and radiators in other antennas.

• Current Optics and Photonics
• /
• v.3 no.4
• /
• pp.304-310
• /
• 2019

In this paper, a microstructured, hexagonal-shaped dual-core photonic crystal fiber (PCF) is proposed. The proposed structure has specific optical properties to obtain high birefringence and short coupling length, for different values of structural parameters varied over a wide range of wavelength. The properties are analyzed using a solid core of silica material. The proposed structure is implemented as a polarization splitter with splitting length of 1.9 mm and a splitting ratio of -34.988 dB, at a wavelength of 1550 nm. The obtained bandwidth in one band gap of about 81 nm. The numerical analysis ensures that the performance of the proposed polarization splitter is better than that of existing ones.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.473-477
• /
• 2003

In this paper, a integrated structure of a two-element microstrip patch antenna with two feeds for GPS/PCS dual-band operation is proposed. The radiating element for PCS operation is a novel broad band low-profile cylindrical monopole top-loaded with a shorted meander patch, which gives linearly polarized conical radiation pattern and size reduction of patch due to meander line. The radiating element for GPS operation is a novel square-ring microstrip patch with truncated corners and slits. which provide circularly polarized broadside radiation patterns and size reduction due to slots. using dielectric substrate in GPS antenna of proposed antenna provide to improve isolation between two feeds and reduce size of patch. The proposed antenna achieves the bandwidth and polarization requirements of GPS and PCS systems.

• Proceedings of the KIEE Conference
• /
• 1987.07a
• /
• pp.82-85
• /
• 1987

Electromagnetic waves from the satellite may be utilized to direct the tracking antenna toward the satellite. We design and fabricate the feed appropriate to the monopulse tracking technique which derive angle-error information on the basis of a single pulse. The feed consists of five cavity-backed turnstile elements mounted on a common ground plane. The turnstile dipole are connected to a set of five quadrature hybrids which convert the dual linear polarization into dual circular polarization. The five feed outputs are then processed in the monopulse comparator which is constructed in microstrip for compactness.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.9 s.100
• /
• pp.893-902
• /
• 2005

We propose a novel single-feed triangular patch antenna with bar-type slots for dual-band circular polarization operation. And also propose a H-type slotted triangular patch antenna to enhance the ratio of the resonance frequencies. 3 cases of desist examples with bar-type slots were investigated and also 4 cases of H-slotted antennas were investigated to meet the dual-band requirement for GPS(Global Positioning System) and DMB(Digital Multimedia Broadcasting). One suitable design example was implemented and measured. Simulation results of the design example for GPS and DMB system show that axial ratio and maximum gain are 3.80 dB, 8.85 dBi for low-band at 1.575 GHz and 2.02 dB, 8.60 dBi for high-band at 2.642 GHz, respectively. Measured results of the implemented antenna show that $S_{11}$ is -12.43 dB for low-band at 1.575 GHz and less than -18.75 dB for high-band, respectively.