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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.