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Multi-band Internal antenna for DVB-H and GSM services
Jeongpyo Kim,Giho Kim,Wonmo Seong,Jaehoon Choi 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7
We propose a multi-band internal antenna for the DVB-H and the GSM services. The proposed antenna consists of a tunable PIFA for the DVB-H service and a dual band folded monopole for the GSM 900 and the DCS 1800. The resonant frequencies of the designed antenna are independently adjusted. It can be used for a complex mobile set for a broadcasting service.
Design of an ultra wide-band printed monopole antenna using FDTD and genetic algorithm
Kim, Jeongpyo,Yoon, Taeyeoul,Kim, Jaemoung,Choi, Jaehoon IEEE 2005 IEEE microwave and wireless components letters Vol.15 No.6
This letter presents an ultra wide-band (UWB) antenna with a printed monopole structure fed by a coplanar waveguide (CPW) line. The antenna is analyzed by using the finite-difference time-domain (FDTD) method and genetic algorithm (GA) to achieve an ultra wide bandwidth characteristic. The measured frequency response shows an impedance bandwidth of 7.25GHz or 104.7% over 3.3 to 10.55GHz for VSWR less than 2.
Varactor-tuned microstrip bandpass filter with wide tuning range
Kim, Jeongpyo,Choi, Jaehoon Wiley Subscription Services, Inc., A Wiley Company 2008 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.50 No.10
<P>In this study, a tunable bandpass filter with a hairpin line resonator and loading capacitors using varactor diodes was proposed. The filter was modified by adding varactor diodes to the coupling part to compensate for losses. The designed filter had a simple structure and the characteristics of wide tuning range of 87.9% from 430 to 1105 MHz and low insertion loss of less than 4.42 dB. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2574–2577, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23745</P>
A Tunable Internal Antenna With an Epsilon Negative Zeroth Order Resonator for DVB-H Service
Jeongpyo Kim,Giho Kim,Wonmo Seong,Jaehoon Choi IEEE 2009 IEEE transactions on antennas and propagation Vol.57 No.12
<P>A tunable internal antenna with an epsilon negative zeroth order resonator (ENG-ZOR) for digital video broadcasting-handheld service is proposed in this paper. The antenna consists of two helical radiators, an ENG ZOR with two inductors and a variable capacitor to adjust the resonant frequency. The resonant frequency of the designed antenna can be swept from 474-702 MHz by adjusting the capacitance of the variable capacitor by controlling the DC bias voltage. The proposed antenna has a very compact size of 40 mm times 5 mm times 5 mm.</P>
Design of a multiantenna structure for WCDMA and Wibro MIMO systems using ENG-ZOR unit cells
Kim, Jeongpyo,Choi, Jaehoon Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS - Vol.52 No.1
<P>We propose an internal multiantenna structure for WCDMA and Wibro MIMO systems using epsilon negative zeroth order resonator (ENG-ZOR) unit cells. The proposed multiantenna consists of a dual resonant antenna for the WCDMA band and a MIMO antenna with two antenna elements and an isolator for the Wibro band. The designed multiantenna has the measured peak gains of 3.8 dBi at WCDMA lower band, 1.4 dBi at WCDMA higher band, 1.2 dBi for antenna #2, and −0.95 dBi for antenna #3 at Wibro band. In addition, the isolation characteristic at the Wibro band is higher than 17 dB. The total size of the designed antenna is 40 mm × 7 mm × 5 mm. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 13–17, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24826</P>
The Design of a Sub-harmonic Dual-Gate FET Mixer
Jeongpyo Kim,Hyok Lee,Jaehoon Choi 한국전자파학회JEES 2003 Journal of Electromagnetic Engineering and Science Vol.3 No.1
In this paper, a sub-harmonic dual-gate FET mixer is suggested to improve the isolation characteristic between LO and RF ports of an unbalanced mixer. The mixer was designed by using single-gate FET cascode structure and driven by the second harmonic component of LO signal. A dual-gate FET mixer has good isolation Characteristic since RF and LO signals are injected into gate1 and gate2, respectively. In addition, the isolation characteristic of a sub-harmonic mixer is better than that of a fundamental mixer due to the large frequency separation between the LO and RF frequencies. As RF power was - 30 dBm and LO power was 0 dBm, the designed mixer yielded the - 47.17 dBm LO-to-RF leakage power level, 10 dB conversion gain, - 2.5 dBm OIP3, - 12.5 dBm IIP3 and - 1 dBm 1 dB gain compression point. Since the LO-to-RF leakage power level of the designed mixer is as good as that of a double-balanced mixer, the sub-harmonic dual-gate FET mixer can be utilized instead.
Reconfigurable Multi-Band Mixer for SDR System
Jeongpyo Kim,Jaehoon Choi 한국전자파학회JEES 2007 Journal of Electromagnetic Engineering and Science Vol.7 No.4
A reconfigurable multi-band mixer for the SDR system is proposed. The proposed reconfigurable mixer is operated between 850 ㎒~2 ㎓, which includes all commercial mobile communication service. Because the varactor diodes are used to select a specific frequency and to adjust the impedance characteristic of the selected frequency band, the proposed reconfigurable mixer can be achieved to similar performance across all of the tuning range. In addition, the designed reconfigurable mixer is applicable for the SDR system since it has a single signal path for the multi-band signals and wide band tuning range.