• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.1
• /
• pp.119-126
• /
• 2019

In this paper, a monopole antenna applicable to WLAN standardization is designed, fabricated, and tested. The proposed antenna is designed to have three microstrip lines based on microstrip feeding method and inserted one stub to enhance impedance characteristics. Then, it obtained triple band characteristics of the proposed antenna. We adjusted and optimized the lengths and width of the three microstrip lines and one inserted stub to obtain the required impedance bandwidth for this paper. The proposed antenna has $23.0mm(W){\times}53.1mm(L1)$ on a dielectric substrate of $24.0mm(W1){\times}60.0mm(L){\times}1.0mm$ size. From the fabrication and measurement results, bandwidths of 158 MHz (841 to 1000 MHz) for 900 MHz band, 630 MHz (2.32 to 2.95 GHz) for 2400 MHz band, and 1,040 MHz (4.95 to 5.99 GHz) for 5000 MHz band were obtained based on the impedance bandwidth. The fabricated antenna also obtained the measured gain and radiation pattern characteristics in the required triple band of the proposed antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.5
• /
• pp.492-501
• /
• 2013

In this paper, a multi polarization reconfigurable microstrip antenna that can be used selectively for four polarizations(vertical polarization, horizontal polarization, right hand circular polarization, left hand circular polarization) at the S-band is presented. The proposed antenna consists of four PIN diodes and a microstrip patch with a cross slot and a circular slot and is fed by utiliting electromagnetic coupling between the microstrip patch and the feed line. The proposed antenna has a DC bias network to supply DC voltage to each PIN diode and the polarization can be determined by controlling the ON /OFF states of four PIN diodes. The fabricated antenna has a VSWR below 2 in the vertical polarization(3.17~3.21 GHz), the horizontal polarization(3.16~3.20 GHz), the left hand circular polarization (3.08~3.19 GHz), and the right hand circular polarization(3.10~3.2 GHz) frequency bands. The designed antenna has the cross polarization level higher than 20 dB, a gain over 5 dBi for the linear polarization states, and 3 dB axial ratio bandwidth wider than 50 MHz in the circular polarization states.

• ETRI Journal
• /
• v.27 no.3
• /
• pp.243-249
• /
• 2005

A mobile antenna for multimedia communications with Ku-band geostationary satellite KOREASAT-3 and JSAT-2A is presented. The forward link of the satellite communication is 11.7 to 12.75 GHz, and the return link is 14.0 to 14.5 GHz. The mobile antenna is designed to be a stair structure using 24 active phased array elements in order to provide a low profile, and to be at a non-periodic array distance using the genetic algorithm. Also, the designed antenna uses the double beam forming method for stable satellite tracking. The fabricated mobile antenna is examined using various experiments to confirm its capability for practical application. From the measured results, the fabricated mobile antenna system is confirmed to have a good performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.2 s.105
• /
• pp.178-183
• /
• 2006

The proposed triple-band compact chip antenna using coupled meander line and stacked meander structure for mobile RFID/PCS/WiBro. The proposed antenna is designed to operate at 900, 1,800, and 2,350 MHz, and is realized by parasitic coupled and stacked a meander line. Meander lines are using extend length of effective current path more than monopole and contribute miniaturization. The coupled meander line controls the excitations of the mobile RFID and PCS, stacked meander line controls the excitation of the WiBro. The fabricated antenna size is $10.98{\times}22.3{\times}0.98\;mm$. The resonance frequencies are 905 MHz, 1.77 GHz and 2.32 GHz. The impedance bandwidths are 24 MHz, 140 MHz and 92 MHz. The maximum gains of antenna are 0.34 dBi, 2.58 dBi and 0.4 dBi at resonance frequencies.

• Journal of Advanced Navigation Technology
• /
• v.22 no.5
• /
• pp.449-455
• /
• 2018

For the size reduction, we propose a microstrip-fed monopole antenna with half X-slot in the radiation patch and cover WLAN dual band 2.4 GHz band (2.4 ~ 2.484 GHz) and 5 GHz band (5.15 ~ 5.825 GHz). The frequency characteristics such as impedance bandwidth and resonant frequencies were satisfied by optimizing the numerical values of various parameters, while the reflection loss in 5 GHz was improved by using defected ground structure (DGS). The proposed antenna is designed and fabricated on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of $24{\times}41mm^2$. The measured impedance bandwidths (${\mid}S_{11}{\mid}{\leq}-10dB$) of fabricated antenna are 450 MHz (2.27 ~ 2.72 GHz) in 2.4 GHz band and 1340 MHz (4.79 ~ 6.13 GHz) in 5 GHz band which sufficiently satisfied with the IEEE 802. 11n standard in dual band. In particular, radiation patterns which are stable as well as relatively omni-direction could be obtained, and the gain of antennas in each band was 1.31 and 1.98 dBi respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.5 s.347
• /
• pp.147-155
• /
• 2006

In this paper, we propose a new Mushroom-like PBG concepts for designing with forbidden frequency band-gap at low frequency. These design rules are based on enhancing the capacitance per unit area using modified top-patch of mushroom PBG with no increase on the overall thickness of the substrate board. Also, in this paper, a new approach to suppress the surface wave from antenna is proposed by embedding compact mushroom PBG in the substrate. Comparisons between the results from a conventional patch antenna to a patch antenna on a PBG substrate show that the reduction in the surface wave level is remarkable. This can be observed in the radiation pattern and the maximum gain. The maximum gain for reference patch antenna is $6.43dB{\imath}$ at 5.37 GHz, while the maximum gain for the patch antenna with normal mushroom and vane mushroom PBG is $7.24dB{\imath}\;and\;7.53dB{\imath}$at 5.14 GHz. The back radiation is also considerably reduced; this will lead, of course, to an increase in the antenna efficiency.

• Journal of electromagnetic engineering and science
• /
• v.5 no.1
• /
• pp.31-35
• /
• 2005

This paper presents low form factor dual polarized antenna incorporating low profile annular ring patch antenna having 90$^{\circ}$ phase delay element for circular polarization(CP) and a reactive-loaded monopole linear polarized(LP) antenna. Both types of receiving antennas operate in the same frequency region from 2.320 GHz to 2.345 GHz, while different polarizations are used to take advantage of polarization diversity. The proposed CP antenna has good broadside radiation patterns, while the LP antenna reveals monopole-like radiation patterns. The gains of the antennas are measured to be 1.93 dBi and 2.24 dBi for CP and LP, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.11
• /
• pp.1940-1945
• /
• 2006

The small and wideband annular ring slot antenna with eccentric radiating structure and low impedance feedline is presented. This antenna is analyzed by using substrate with permittivity 4.3 and thickness 1mm. As the measured impedance bandwidth of proposed antenna is $118%(S_{11}{\leq}-10dB)$, its bandwidth is much broader than that of conventional annular ring slot antenna.

• ETRI Journal
• /
• v.32 no.5
• /
• pp.827-830
• /
• 2010

For an adaptive cruise control (ACC) stop-and-go system in automotive applications, three radar sensors are needed because two 24 GHz short range radars are used for object detection in an adjacent lane, and one 77 GHz long-range radar is used for object detection in the center lane. In this letter, we propose a single sensor-based 24 GHz radar with a detection capability of up to 150 m and ${\pm}30^{\circ}$ for an ACC stop-and-go system. The developed radar is highly integrated with a high gain patch antenna, four channel receivers with GaAs RF ICs, and back-end processing board with subspace based digital beam forming algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.1
• /
• pp.24-29
• /
• 2015

In this paper, we propose a method of isolation improvement for broadband antennas using a high-permeability substrate. The substrate is applied for a planar monopole antenna based on near-field analysis to maintain radiation characteristics at its operating frequency while improving isolation by minimizing mutual coupling with nearby antennas at other frequency bands. To verify isolation improvement, we compare performance variations of $S_{21}$ according to the existence of the substrate using the proposed antenna and a reference antenna whose operating frequency is 2 GHz. As a result, the radiation characteristics are maintained, and $S_{21}$ performance is improved by more than 5~10 dB in the frequency band of greater than 2 GHz, which demonstrates the isolation can be improved by using the high-permeability substrate.