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Broadbanding of a Planar Antenna with Three Frequency Bands and Its Application
Hiroyasu Matsui,Toshio Wakabayashi 한국전자통신연구원 2007 ETRI Journal Vol.29 No.6
This paper describes a line element planar antenna with three frequency bands. To obtain broadband characteristics, a modified planar antenna that has semielliptical elements based on the characteristics of a line element planar antenna is proposed and analyzed by the finite difference time domain method. Return loss characteristics are discussed as functions of the eccentricity values of semi-ellipse at each element. The broadbanding of the modified planar antenna is implemented based on the results. The planar antenna with three systems (an 800 MHz band cellular phone, a third-generation cellular phone, and a 2.4 GHz band wireless LAN system) is considered as an application example.
Internal Bias Field in Glycine Phosphite Crystal
Jannatul Nayeem,Toshio Kikuta,Hiroshi Wakabayashi,Noriyuki Nakatani,Toshinari Yamazaki 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.IV
The distributions of internal bias eld Eb have been investigated under the carbon-powder pattern and mercury electrode techniques in GPI ferroelectric crystals. Polarity and intensity of Eb are distributed depending on crystal growth sectors. Crystal symmetry 2/m is observed obviously in the distribution of Eb. The polarities of Eb are head-to-head manner in those growth sectors where a surface is growing parallel to the crystallographic a-axis and tail-to-tail manner in the other growth sectors in the crystal. The maximum intensity of Eb is found in the sectors f010g where the growing surfaces are perpendicular to the ferroelectric b-axis.
Multiband Microstrip-Fed Right Angle Slot Antenna Design for Wireless Communication Systems
Paitoon Rakluea,Noppin Anantrasirichai,Kanok Janchitrapongvej,Toshio Wakabayashi 한국전자통신연구원 2009 ETRI Journal Vol.31 No.3
This paper presents a novel multiband microstrip-fed right angle slot antenna design technique for multiple independent frequency bands. The new technique uses various slot sizes at various appropriate positions. We first propose a tri-band slot antenna consisting of three right angle slots. Then, a quad-band slot antenna is developed with four right angle slots which achieves slant ±45° linear polarization, omnidirectional pattern coverage, good antenna gain, and acceptable impedance bandwidths over all the operating frequency range. Moreover, an opencircuited tuning stub is introduced to achieve good impedance matching. Both proposed antennas are designed on a ground plane of RT/duroid 5880 substrate with a thickness of 1.575 mm. The real measurable results show that the desired frequencies used in wireless communication systems, namely, WLAN and WiMax, are efficiently achieved.
Controllable Band-Notched Slot Antenna for UWB Communication Systems
Weerathep Kueathaweekun,Noppin Anantrasirichai,Chawalit Benjangkaprasert,Jintana Nakasuwan,Toshio Wakabayashi 한국전자통신연구원 2012 ETRI Journal Vol.34 No.5
We propose a slot antenna consisting of a rectangular slot on the ground plane, fed by a microstrip line with a rectangular-ring-shaped tuning stub that can be deployed in ultra-wideband (UWB) communication systems to avoid interference with wireless local area network (WLAN) communication. Our antenna can achieve a single band-notched property from the 5 GHz frequency to the 6 GHz frequency owing to a controllable band notch that uses L- and J-shaped parasitic elements. The antenna characteristics can be modified to tune the band-notched property (4 GHz to 5 GHz or 6 GHz to 7 GHz) and the bandwidth of the band notch (1 GHz to 2 GHz). Furthermore, the shifted notch with enhanced width of the band notch from 1 GHz to 1.5 GHz is described in this paper. The UWB slot antenna and L- and J-shaped parasitic elements also provide the band-rejection function for reference in the WiMAX (3.5 GHz) and WLAN (5 GHz to 6 GHz) regions of the spectrum. Experiment results evidence the return loss performance, radiation patterns, and antenna gains at different operational frequencies.