• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1261-1268
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• 2019

In this paper, we present the analysis of a novel monopole antenna with a reflector. The proposed monopole antenna is printed on a TRF-45 substrate, and the reflector, which is positioned near the base of the antenna, is printed on the FR-4 substrate. Positioning the reflector near the base of the antenna was found to suppress current radiation toward the back of the monopole antenna. Comparative analysis of the proposed monopole antenna and a conventional monopole antenna without a reflector revealed that the bandwidths of the antenna with and without a reflector were 2.65 GHz and 2.88 GHz, respectively. Additionally, the antenna without a reflector was observed to have a bi-directional radiation pattern in the E-plane, and an omni-directional radiation pattern in the H-plane. However, only the antenna with a reflector was found to suppress back radiation, and provide non-uniform directional radiation in the E-plane and H-plane.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.511-519
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• 2003

In this paper, to achieve a broad-band and high-gain antenna, we thus designed and analyzed the CRLPDA(Corner Reflector Antenna feeding by Log-Periodic Dipole Antenna) made up of 90$^{\circ}$corner reflector, which is trough-reflector type installed a planar reflector at the folded line. CRLPDA for operating frequency band of 1,400 MHB ~ 2,400 MHz was designed and radiation characteristics of the designed antenna were analyzed by moment method. To verify the analysis results, CRLPDA was fabricated and the calculated results were compared with the measured results. The measured results showed good agreement with the calculated results. As the result of measurements, bandwidth(VSWR＞2) for 1,000 MHz was achieved and gain was 13 dBi.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.1-10
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• 1999

In this paper, the design for the shaped offset cassegrain antenna system combined with corrugated feed horn is presented. First, spherical-mode wave theory is applied to the corrugated conical horn and its radiation patterns are investigated. Using the radiation patterns, design data of the corrugated conical horn are obtained by efficiency investigation of horn antenna. When the investigation is completed, the flare angle and length of the corrugated conical horn is determined. Next, the main and sub-reflector is designed using Snellis law and the conservation principle of energy. Then the uniform direction and energy density of the traveling wave at the aperture of the main-reflector is obtained. The maximum size of the main-reflector is determined by investigation of the illumination and spillover efficiency. Finally, the curvature of the main-reflector is modified to satisfy the condition of the uniform phase. From the calculated efficiencies, the designed site of the main-reflector and sub-reflector, system gain of the shaped offset cassegrain antenna has been obtained 40.5dB in Ka-band frequency. It has better characteristics than the result of SABOR with 39dB gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.8
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• pp.766-773
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• 2016

This paper proposes an aircraft-installed compact offset-parabolic-reflector antenna for the spinning direction-finding applications. The feeder of the reflector antenna is a LPDA antenna that has the ultra-wideband characteristics and the $45^{\circ}$ slant linear polarization. The reflector is designed to be slanted by $5^{\circ}$ in the elevation and to be small in size on the basis of the reference parabolic shape for the purpose of the high gain and mounting on the underside of aircraft fuselage. Over the ultra-wideband 20:1 bandwidth from S to Ka band, the measured average gain of the proposed antenna is 27.97 dBi, and the average half-power beam width is $4.55^{\circ}$ in the azimuth and $4.3^{\circ}$ in the elevation which is the pencil-beam radiation pattern. All the measured data are similar to the simulation results. The designed compact offset-parabolic-reflector antenna that is installed in the limited area has the ultra-wideband and high-gain characteristics. We expect that the newly designed antenna can be applied to the spinning direction-finding antenna system installed in an aircraft.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.67-71
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• 2012

This paper represents the impact analysis results of antenna reflector for the UHF-band antenna of Space Launch Vehicle. Three types of UHF-band antenna reflector model have been proposed and simulated to compare their characteristics such as resonance frequency, reflection loss and radiation pattern etc. Simulation results showed that resonance frequency and return loss of each reflector models were rarely affected even if reflector sizes are changed. The antenna gain and 3dB bandwidth were slightly changed to the worse directions as the reflector sizes are smaller.

• Journal of electromagnetic engineering and science
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• v.16 no.4
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• pp.206-209
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• 2016

This letter proposes a reconfigurable directional coupler that uses a variable impedance mismatch reflector to achieve high isolation characteristics in the antenna front end. The reconfigurable coupler consists of a directional coupler and a single-pole four-throw (SP4T) switch with different load impedances as a variable load mismatch reflector. Selection of the load impedance by the reflector allows cancellation of the reflected signal due to antenna load mismatch and the leakage from the input to isolation port of the directional coupler, resulting in high isolation characteristics. The performance of the proposed architecture in separating the received (Rx) signal from the transmitted (Tx) signal in the antenna front end was verified by implementing and testing the reconfigurable coupler at 917 MHz for UHF radio-frequency identification (RFID) applications. The proposed reconfigurable directional coupler showed an improvement in the isolation characteristics of more than 20 dB at the operation frequency band.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1047-1052
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• 2016

In this paper, we propose the CSLR(: Complementary Single Loop Resonators)-loaded inset fed patch antenna with a conducting reflector to improve the radiation patterns. Reflector of the proposed antenna is located below about ${\lambda}_0/4$ from the ground plane of the patch, the size is about two times of the patch. The proposed antenna is designed and fabricated on the substrate which has a dielectric constant and thickness with 2.5 and 0.787 mm, respectively. Simulation results are obtained by using the HFSS, 3D EM Solver based Finite Element Method(: FEM). The resonant frequency and matching characteristics of the antenna with reflector are substantially the same as when there is no change in the antenna without reflector, it is confirmed that radiation patterns are significantly improved by the reflector.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.3
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• pp.340-350
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• 1999

In this paper, W-type reflector antennas modified from corner reflector antenna structure were proposed and the radiation characteristics were analyzed using the method of moments. The analysis results such as gain, F/B, half power beamwidth, and radiation pattern are presented as functions of dipole height h and back edge spacing d. Also, the proposed antenna was compared with corner reflector antennas in the same size of side reflectors, W-type reflector antenna was found to exhibit somewhat higher gain and larger F/B than corner reflector antennas. To verify the analysis results, W-type reflector antenna was fabricated and the radiation characteristics were measured. The measured results show good agreement with the calculated results.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.545-548
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• 2002

This paper proposes a unidirectional beam antenna using a probe excited circular ring near the reflector. The antenna structure is simple. The radiation characteristics of the antenna fur various spacing between a probe excited circular ring and the reflector are analyzed. These characteristics are also compared with the conventional single aperture near the reflector. It is found that the proposed structure yields better characteristics than the conventional structure. The numerical results of the radiation pattern, elevational beam peak, beamwidth, and maximum directivity are investigated. The result of the analysis is very useful to design the antenna of the high directivity with unidirectional beam.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.989-996
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• 2017

The proposed directional pencil beam antenna consists of a waveguide feeder with bended elliptical conductor plate feed and a parabolic curved reflector. Two rectangular apertures located at the broad wall near the end of the feed waveguide inserted from behind the reflector are located at the focus of the reflector and emit electromagnetic energy with bended elliptical conductor plate. This plate is designed to reflect electromagnetic energy primarily and to face the main reflector. The two rectangular apertures located at the waveguide end have inwardly protruding tabs for impedance matching of the antenna system, the shape of the tabs is a truncated oval. The proposed parabolic reflector antenna has a diameter of 400 mm and a focal length of 134.23 mm. The antenna gain is 33.68 dBi at the center frequency of 16.5 GHz, the beam width is $3.3^{\circ}$ and the reflection loss is -15 dB. Using the HFSS-IE, simulation results are performed to validate the proposed antennas.