• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.1
• /
• pp.26-32
• /
• 2002

When a spatial method of moments(MoM) is used in conjunction with closed-form Greens functions for the analysis of a general microstrip structures of thin or thick substrate, an efficient technique fur the evaluation of MeM off-diagonal matrix elements as well as diagonal elements is proposed. In order to check the validity of the present method, performance is demonstrated for the example of a coaxially-fed microstrip antenna and the present results are compared with the previous results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.2
• /
• pp.152-163
• /
• 2010

In this paper, a cavity-backed high gain dual band microstrip antenna with Frequency Selective Surface space(FSS) for WLAN is proposed. The proposed antenna that operates in IEEE 802.11a/b bands with similar radiation pattern and gain is fabricated on RO4003 substrate with a dielectric constant of 3.38. The size of the antenna is $71.5{\times}42.0{\times}6.6\;mm^3$, and the FSS size is $120.0{\times}120.02\;mm^3$. The ground plane size including cavity is $150.0{\times}145.0\;mm^3$. The antenna is fed by coaxial cable. The simulated bandwidths of the antenna are 2.369~2.517 GHz and 5.608~5.833 GHz for VSWR<2. The gains are 11.23 dBi and 12.60 dBi, respectively, for the lower and upper bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.5
• /
• pp.416-423
• /
• 2016

In this paper, a conformal type $1{\times}4$ microstrip patch array antenna with tilted antenna beam is presented for UWB sensor applications. Each antenna element comprises E-shaped patch with L-probe feeding to increase the bandwidth. The tilted antenna beam of 20 degree can be achieved with 42 ps microstrip delay lines at the series feeding network with T-junctions. The measured reflection coefficient is >9 dB at 3.5~4.5 GHz. The measured antenna gain and HPBW are >10 dBi and <30 degree at 3.75~4.25 GHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.5
• /
• pp.209-215
• /
• 2017

In this paper, an antenna having 2-axes cross monopulse for Ka band millimeter-wave seeker is designed and antenna performance is verified through vacuum-brazing method for fabrication and measurement. Also, by designing and manufacturing a waveguide circulator the antenna including the circulator is measured. Radiating part of the antenna takes optimized slot lengths and offsets from Elliot's array synthesis procedure using the generic algorithm and feeding part for cross monopulse axes uses the folded waveguide to optimize the S-parameter result. Based on this method, the antenna has 33.3 dBi gain, $3.5^{\circ}{\pm}0.5^{\circ}$ beamwidth, below -23 dB SLL through fabricating and measuring. It is found that antenna characteristics is similar to design results.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.12
• /
• pp.139-145
• /
• 2008

In this paper, a microstrip surface wave antenna(SWA) with a frequency selective surface structure(FSS) is designed and measured. A microstrip SWA has many advantages such as low profile, low weight, easy fabrication, and compatibility with monolithic microwave integrated circuits(MMIC). In addition, it has demonstrated monopole like beam patterns. The microstrip SWA consists of two parts : a center-fed modified microstrip patch to excite surface wave, and a periodic patches to support the propagation of the surface waves. To obtain wide bandwidth, the ring type parasitic element is inserted and the circular patch is selected for the unit element in FSS structure. Experimental results show that the microstrip SWA has monopole like beam patterns at 5.9GHz. Impedance bandwidth and gain is 12% and 5.6dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.12
• /
• pp.1340-1350
• /
• 2009

The design and implementation of planar Active Phased Array Antenna System are described in this paper. This Antenna system operates at X-band with its bandwidth 10 % and dual polarization is realized using dual slot feeding microstrip patch antenna and SPDT(Single Pole Double Through) switch. Array Structure is $16\times16$ triangular lattice structure and each array is composed of TR(Transmit & Receive) module with more than 40 dBm power. Each TR module includes digital attenuator and phase shifter so that antenna beam can be electronically steered over a scan angle$({\pm}60^{\circ})$. Measurement of antenna pattern is conducted using a near field chamber and the results coincide with the expected beam pattern. From these results, it can be convinced that this antenna can be used with control of beam steering and beam shaping.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.12 s.103
• /
• pp.1179-1185
• /
• 2005

In this paper, novel internal antenna with its controllable resonant frequency is presented for triple-band or over mobile handsets. The operating range can include GSM(880${\~}$960 MHz), GPS(1,575$\pm$10 MHz), DCS(1,710${\~}$1,880 MHz), US-PCS(1,850${\~}$l,990 MHz), and W-CDMA(1,920${\~}$2,170 MHz). The proposed antenna is realized by combination of a half wavelength loaded line and a shorted monopole. A single shorting and feeding points are used and they are common to both antenna structures. By controlling a value of lumped inductance element between shorting point and ground plane, the antenna provides enough bandwidth to cover DCS, US-PCS, and W-CDMA respectively. When these higher bands are controlled by the values of inductance, resonant characteristics in GSM and GPS bands are maintained. In this work, maximum value of the inductor is limited within 3.3 nH to mitigate gain degradation from frequency tuning. As a result, measured maximum gain of antenna is -0.58${\~}$-0.30 dBi in the GSM band, -0.57${\~}$0.43 dBi in the GPS band and 0.38${\~}$1.15 dBi in the DCS/US-PCS/W-CDMA band. In higher band, the proposed antenna is certified that resonant frequency of about 240 MHz can be effectively controlled within gain variation of about 0.77 dB by simulation and measurement.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.10
• /
• pp.2223-2231
• /
• 2015

In this paper, we propose a built-in antenna for wireless USB dongle which has a modified structure from the existing planar monopole antenna. The proposed antenna implemented a dual-band characteristic by inserting Strip1, Strip2, Strip3 into the monopole structure combined with 'n' shape and feeded 50-Ω using coaxial cable. The antenna is designed on an FR-4 substrate of which the dielectric constant is 4.6, and its overall size is 10 mm × 50 mm × 1mm. Based on the measurement results of the return loss, it was confirmed to satisfy the dual band resonance characteristics of 740 MHz (2.3 ~ 2.7 GHz) and 1,200 MHz (5.15 ~ 5.825 GHz) by -10 dB. In addition, we obtain the omni-directional radiation pattern measurements in the operating frequency bands, and the maximum gain of the proposed antenna has 2.26~3.81 dBi in the 2.4 GHz band and 2.21~5.79 dBi. in the 5.5 GHz band, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.4
• /
• pp.387-392
• /
• 2014

In this paper, the broadband antenna design, which can be applied to USB Dongle, supporting Wibro(2.3~2.4 GHz), Wi-Fi(2.4~2.5 GHz) and LTE7(2.5~2.7 GHz) is proposed technique. The proposed antenna was designed similar to PIFA type antennas. Reactive elements were used to control the input impedance and wideband characteristics were achieved by controlling coupling between the feed structure and the radiator. As a result, the antenna printed on FR-4 PCB(${\epsilon}_r$ =4.4, tan ${\delta}$=0.02) occupying an area of $15{\times}5mm^2$ was able to achieve bandwidth of 1 GHz from 2.1 to 3.1 GHz under VSWR=2. Measured return loss characteristics, bandwidth and radiation patterns were in good agreement with the simulated results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.11
• /
• pp.1225-1232
• /
• 2009

In this paper, a parabolic edge planar monopole antenna for indoor DTV reception is presented. The antenna has broadband property with the planar monopole and ground of parabolic edges. It is designed close to self-complementary structure as changing curvature of edges of monopole and ground. Monopole and ground conductors of the antenna are on the same plane, and excited through CPW feeding. It is fabricated on an FR4 dielectric substrate of $\varepsilon_r=4.4$, and the dimension is $40\;mm{\times}200\;mm{\times}1.6\;mm$. Return loss is larger than 10 dB in 470~806 MHz. Maximum gain is 1.86 dBi on E-plane at 810 MHz and 3.86 dBi on H-plane at 600 MHz.