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A novel dual band-notched monopole ultra-wideband antenna is proposed, in which the parasitic strip creates one band-notch at 5.5 GHz and the tuning stub produces another band-notch at 3.5 GHz.The experimental results show that the proposed antenna, with a compact size of 20 ϫ 31.5 mm 2 , has a bandwidth of 3. 1-10.6 GHz with voltage standing wave ratio (VSWR) less than 2, except the bandwidths of 3. INTRODUCTIONWith the development of modern wireless and mobile communication, the ultra-wideband systems have attracted much attention recently because of its great advantages including high speed data rate, small size, and low power consumption. However, according to IEEE 802.11a, HIPERLNA/2, and IEEE 802.16, some narrow bands, such as WLAN systems (5.15-5.825 GHz) and WIMAX systems (3.3-3.7 GHz), exist during the bandwidth of ultra-wideband (3.1-10.6 GHz). Therefore, to avoid EM interferences between these systems and UWB communication systems, a band elimination characteristic is necessary in UWB antennas. Recently, several UWB antennas with frequency band-rejection function have been reported [1][2][3][4][5][6]. But, most of the proposed antennas only have one band-notched characteristics [1][2][3]. Two UWB antennas with dual band stops have recently been proposed [4, 5]. The dual band stops are formed by cutting two or three U-shaped or C- shaped slots into antenna. Because of the allocation, shape, width, and length of the slots have intensive influence to the bandrejection characteristic, it is difficult to fabricate and adjust the central frequencies of the notched bands.In this letter, a simple UWB antenna with a novel dual bandnotched structure is proposed. By using the parasitic strip and the tuning stub, dual band stops will be created. By only changing the lengths of the parasitic strip and the tuning stub, we can alter the central frequencies of the dual notched bands easily and separately. In addition, there is no sensitive variable to control antenna bandnotched characteristic, so it is facile to fabricate. Details of the antenna design are described, and both simulated and measured results are given. Figure 1 illustrates the geometry and configuration of the proposed UWB antenna, which is printed on the FR4 substrate with a thickness of 1 mm and dielectric constant of 4.4. The antenna size is 20 ϫ 31.5 mm 2 , and the feeding structure of 50 ⍀ microstrip line is used. The proposed antenna is composed of a rectangular ground with a parasitic strip [1], a planar rectangular radiation patch with a wide slot, which load a tuning stub [6]. The radiation patch has been beveled, which ensures good impedance match over a broad bandwidth [4]. And the wide slot antenna has the simple structure and supplies the omnidirectional patterns [7]. A parasitic strip is printed on the bottom side of the substrate, which leads band-notched characteristic at 5.5 GHz. The spacing between the ground and the parasitic strip is 1 mm. To obtain another stopband, a tuning stub is inserted to the wide slot [6], whi...

A novel compact quad-band internal antenna for mobile handsets operating the , GPS (1575 Ϯ 10 MHz), DCS (1710 -1880 MHz), and PCS (1850 -1990 bands is proposed and implemented. The proposed antenna consists of a feeding strip, shorting strip, and folded loop radiating element with embedded tuning notches. Embedding the notches changes the current flow on the surface of the loop radiator so that the resonant frequencies can be controlled independently by their size and position. The measured impedance bandwidth (VSWR Ͻ 2) of the proposed antenna is 11.3% at GSM band and 27.4% at higher bands including GPS/DCS/PCS. The measured peak gains are 0.51, 2.06, 0.52, and 1.34 dBi, at the GSM, GPS, DCS, and PCS bands, respectively. ABSTRACT: We describe high-efficiency gratings illuminated by incident lights in the C ϩ L bands as the (de)multiplexers for dense wavelength division multiplexing (DWDM) application. This grating is fabricated in fused silica and replicate in polydimethylsiloxane (PDMS) and polyethylene terephthalate glycol (PETG) with the technology of nanoimprint.

A new type of a compact tag antenna, which can be effectively mounted on metallic objects, is proposed for UHF band RFID systems. The proposed antenna consists of a simple microstrip path and feed line, and it is fabricated on a very thin (1.6 mm) subtrate compared with previous works. The impedance of the proposed antenna can be easily adjusted to match the various impedance values of tag chips by simply changing the length of the feed line only. The antenna is analyzed by simulations by Ansoft HFSS software, and the measured results based on backscattering method are provided. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 232–234, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23031

This paper describes an implementation method and the results of numerical mobile phone models representing real phone models that have been released on the Korean market since 2002. The aim is to estimate the electromagnetic absorption in the human brain for casecontrol studies to investigate health risks related to mobile phone use. Specific absorption rate (SAR) compliance test reports about commercial phone models were collected and classified in terms of elements such as the external body shape, the antenna, and the frequency band. The design criteria of a numerical phone model representing each type of phone group are as follows. The outer dimensions of the phone body are equal to the average dimensions of all commercial models with the same shape. The distance and direction of the maximum SAR from the earpiece and the area above -3 dB of the maximum SAR are fitted to achieve the average obtained by measuring the SAR distributions of the corresponding commercial models in a flat phantom. Spatial peak 1-g SAR values in the cheek and tilt positions against the specific anthropomorphic mannequin phantom agree with average data on all of the same type of commercial models. Second criterion was applied to only a few types of models because not many commercial models were available. The results show that, with the exception of one model, the implemented numerical phone models meet criteria within 30%. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ⓒ

A new design method of single‐stub impedance matching networks is presented for the dual‐band application. The dual‐band operating conditions are analyzed in detail and the design equations are derived in concise form for different locations and termination types of the stub line. The proposed impedance matching scheme is successfully applied to the design of a stubbed dual‐band T‐junction power divider. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1359–1362, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25201