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    Selected Abstracts

    Performance analysis of TH-UWB radio systems using proper waveform design in the presence of narrow-band interference

    EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2006
    Hassan Khani
    Ultra-wide band (UWB) radio systems, because of their huge bandwidth, must coexist with many narrow-band systems in their frequency band. This coexistence may cause significant degradation in the performance of both kinds of systems. Currently, several methods exist for narrow-band interference (NBI) suppression in UWB radio systems. One of them is based on mitigating the effects of NBI through proper waveform design. In Reference 1, it has been shown that using properly designed doublet waveform can significantly reduce the effects of NBI on an important kind of UWB radio systems, i.e. BPSK time-hopping UWB (TH-UWB) systems. In this paper, the proper waveform design technique is extended to BPPM TH-UWB systems. It is shown that this method can properly suppress the effects of NBI on the performance of BPPM TH-UWB systems. Copyright © 2005 AEIT. [source]

    Scheduling and power control for MAC layer design in multihop IR-UWB networks

    INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 1 2010
    Reena Pilakkat
    Recently, a number of researchers have proposed media access control (MAC) designs for ultra-wideband (UWB) networks. Among them, designs based on scheduling and power control seem to be of great promise, particularly for quality-of-service (QoS) traffic. We investigate the efficiencies of many different choices for scheduling and power allocation for QoS traffic in a multihop impulse radio (IR)-UWB network, with the objective of achieving both high spectral efficiency and low transmission power. Specifically, we compare different scheduling schemes employing a protocol interference-based contention graph as well as a physical interference-based contention graph. We propose a relative distance to determine adjacency in the protocol interference-based contention graph. Using our improved protocol interference model with graph-based scheduling, we obtained better performance than the physical interference-based approach employing link-by-link scheduling. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Microstrip-fed cusp antenna for ultra-wide band communication systems

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2009
    Ezzeldin A. Soliman
    Abstract A novel antenna for ultra-wideband (UWB) applications is presented in this article. The proposed antenna consists of one circular patch placed on one side of a substrate and one circular slot placed on the other side. The antenna is fed with a microstrip line connected to the circular patch. The radii of the circular patch and slot and the separation between their edges represent the three design parameters which are optimized such that the antenna satisfies the design specifications. The proposed antenna has been fabricated using printed circuit board (PCB) technology. It has been characterized both theoretically and experimentally. The measured and calculated results are presented, compared, and discussed. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009. [source]

    Compact top-loaded ultra-wideband biconical antenna for indoor base-station applications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2010
    W. J. Lu
    Abstract A biconical antenna employing the top-loaded technique is proposed for ultra-band (UWB) operation. The antenna is composed of a small cone mounted on a top-loaded disc and a conical ground plane, with both cones electrically connected together using four shorting pins to reduce the lower cutoff frequency. The antenna is investigated using computer simulation and measurement. Results show that the antenna has an impedance bandwidth from 0.8 GHz to over 11.2 GHz, dipole-like omnidirectional radiation pattern, average gain of about 4.2 dBi, and average radiation efficiency of over 88%. The antenna has the advantageous features of compact size, low profile, simple structure, and ultra-wideband characteristic and so is suitable for indoor base-station applications of many existing and future wireless and UWB systems. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2594,2598, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25540 [source]

    Compact ultra-wideband bandpass filter using defected ground structures

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2010
    J. K. Lee
    Abstract In this letter, a compact ultra-wideband (UWB) bandpass filter (BPF) is presented with improved upper stopband performance using six defected ground structures (DGS). The proposed BPF is composed of seven DGSs which are positioned under the input and output microstrip line and coupled double step impedance resonator (CDSIR). By using CDSIR and open loop defected ground structure (OLDGS), we can achieve UWB BPF characteristics, and by using the conventional DGSs under input and output microstrip line, we can improve upper stopband performance. Simulated and measured results are found in good agreement with each other, showing a wide passband from 3.4 to 10.9 GHz, minimum insertion loss of 0.61 dB at 7.02 GHz and the group delay variation is less than 0.4 ns in the operating band while wide upper stopband with more than 30 dB attenuation up to 20 GHz. In addition, the proposed UWB BPF has a compact size. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2173,2175, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25436 [source]

    Bandwidth enhancement of a coplanar waveguide-fed asymmetrical slot antenna with a rectangular patch

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2010
    Shou-Tao Fan
    Abstract A coplanar waveguide-fed asymmetrical slot antenna with a rectangular patch for bandwidth enhancement is demonstrated. By attaching a rectangular patch to the monopole radiating element, a good performance of bandwidth enhancement for the antenna is achieved. From simulational and experimental results, the enhanced impedance bandwidth of the proposed antenna, defined by ,10 dB return loss, can reach 13.1 GHz, from 2.4 to 15.5 GHz, or about 146% with the center frequency 8.95 GHz, which makes it an excellent candidate for the ultra wideband (UWB, 3.1,10.6 GHz) applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2259,2261, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25476 [source]

    High-performance UWB filter with a controllable notched band

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010
    Chun-Ping Chen
    Abstract This article presents a design of a high-performance ultra-wideband (UWB) bandpass filter with a controllable notched band. Firstly, a UWB filter consisting of a stepped-impedance resonator (SIR) and two shunt short-circuited stubs is synthesized. Then, a narrow controllable notched band is introduced by a coupled external SIR. To be highlighted as an attractive advantage, as the characteristics of the UWB filter are not deteriorated by the placement of the external resonator, no further adjustments is needed for the synthesized UWB filter in this design. As an example, an (Federal Communications Commission) FCC UWB filter with a WLAN notch band is designed, simulated, and fabricated. A good agreement between the measured results and predicted ones validates the newly proposed design scheme and the filter prototype. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1842,1846, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25354 [source]

    A CMOS differential fifth-derivative Gaussian pulse generator for UWB applications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010
    Jin He
    Abstract A CMOS differential fifth-derivative Gaussian pulse generator is presented for Ultrawideband (UWB) applications. The design exhibits low-power consumption, low-circuit complexity, and precise pulse shape to inherently comply with the FCC spectrum mask for indoor UWB applications without the need for a filter. The proposed differential pulse generator was implemented with a 1.8-V, 0.18-,m CMOS process, but only the positive fifth-derivative Gaussian pulse was measured owing to the limitation of the available testing facilities. The measured pulse has peak-to-peak amplitude of 154 mV and a pulse width of 820 ps. Small core area of the differential pulse generator is only 0.028 mm2 because of its all digital circuit design. The average power dissipation is 1.2 mW with a pulse repetition frequency (PRF) of 50 MHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1849,1852, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25342 [source]

    Half-cut disc UWB antenna with tapered CPW structure for USB application

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2010
    Wen-Jian Liu
    Abstract A novel half disc for ultra wide band (UWB) application is proposed with the beveled ground and tapered coplanar waveguide-fed structure. Its impedance bandwidth ranges from 2.42 to 13.62 GHz, which covers the entire UWB band. Its dimension is as small as 11 mm × 29.3 mm. As a result, it can be easily integrated into the wireless USB equipments. The simulated and measured results have a relative good agreement. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1380,1384, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25193 [source]

    Planar ultrawideband antenna array for short-range wireless communications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010
    Osama M. H. Ahmed
    Abstract In this article, novel 2-element and 4-element planar ultrawideband (UWB) antenna arrays with bidirectional radiation patterns based on identical UWB antenna elements for UWB communications applications have been proposed, simulated and experimentally investigated. Each array is constructed by means of feeding omni-directional printed UWB monopole antennas with a UWB power divider. The proposed 2-element antenna array yields an impedance bandwidth of 110% (3.1,10.6 GHz) covering the whole UWB frequency bandwidth while the impedance bandwidth is multi-band in case of the 4-element antenna array because of the increasing effect of mutual coupling among antenna elements. The calculated gain of the 2-element and 4-element array is quite stable with about 3 and 6 dB higher than that of the single element, respectively. Both measured and calculated E-plane radiation patterns of the array and the single element are almost the same while the H-plane radiation patterns of the array are distinctively bidirectional compared to the omni-directional pattern of the single element. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1061,1066, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25140 [source]

    C-shaped ultra-wideband bandpass filter with WLAN notch band

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010
    Pai-Yi Hsiao
    Abstract A compact bandpass filter (BPF) embedded with 5.8 GHz wireless-LAN notch is presented for 3.1,10.6 GHz ultra-wideband (UWB) systems. The proposed UWB-BPF based on a defect-grounded structure is implemented with an FR4 board. Two open-loop resonators on the top layer provide a narrow notch band whose center frequency can be easily adjusted by varying the sizes of the open-loop. A simple C-shaped slot on the bottom ground layer is adopted to improve the bandwidth performance. The characteristics of UWB-BPF are analyzed and simulated using a circuit model of LC lump elements. The size of the filter is at least 34% less than those filters with the same specification. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1215,1218, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25153 [source]

    A novel ultrawideband planar antenna with dual band-notched performance

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010
    Meng Zhang
    Abstract In this article, a novel and compact ultrawideband (UWB) planar antenna is presented. This antenna consists of an annular patch and a 50 , microstrip feed line. The 3.5/5.5 GHz dual band-notched characteristic gets achieved by etching a C-shaped slot in the patch and complimentary split ring resonator (CSRR) structure in the ground. The measured results show that the proposed antenna can achieve the voltage standing wave ratio (VSWR) requirement of less than 2.0 in very UWB frequency range from 3.05 to 23.8 GHz with dual band-rejection performance of 3.4 to 4.0 GHz and 4.92 to 6.0 GHz. Measured VSWR of the proposed antenna is in good agreement with the simulated result. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 90,92, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24856 [source]

    Two new ultra-wideband antennas with 3.4/5.5 GHz dual band-notched characteristics

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2009
    Dan-Hong Bi
    Abstract This letter presents two ultra-wideband (UWB) antennas with 3.4/5.5 GHz dual-notched bands. The U- and V-slots are used to reject the frequency band (3.3,4.2 GHz) limited by C-band satellite communication and Wimax systems. Another rejection band (5.15,5.825 GHz), limited by IEEE 802.11b or HIPERLAN/2 system, is obtained by using the U/V-slot defected ground structure. Experimental results indicate that these antennas cover the entire UWB for voltage standing wave radio <2, except two notched bands. Moreover, these antennas have omnidirectional radiation patterns in the H-plane and good gain flatness. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2942,2945, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24792 [source]

    A fully integrated ultra-low power CMOS transmitter module for UWB systems

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2009
    Tao Yuan
    Abstract A fully integrated CMOS ultra-wideband (UWB) transmitter module is proposed for UWB applications. The transmitter module consists of a band-notched UWB antenna and a transmitter IC which integrates a pulse generator, a gating signal generator and driver amplifiers (DAs). The drive amplifier uses a two-stage amplifier,a Class-E amplifier and a Class-A amplifier with switch control, to significantly reduce power consumption (522 ,W/20 Mbps). Fabricated using a 0.18-,m CMOS process, the generated pulse then passes through the DA, which not only drives the antenna but also shapes the generated digital signal to meet the Federal Communications Commission spectral mask specification. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2318,2323, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24632 [source]

    An ultra-wideband bandpass filter using hybrid structure of microstrip and CPW

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2009
    Xun Luo
    Abstract An ultra-wideband (UWB) bandpass filter is proposed based on the hybrid structure of microstrip and coplanar waveguide (CPW). First, the detached-mode resonator is formed on the CPW layer, which composes a quarter-wavelength (,/4) multiple-mode resonator (MMR) with a short-stub and a ,/4 single-mode resonator. Then, two ,/4 microstrip open-stubs on the top side of the common substrate are introduced for bandwidth enhancement to meet the UWB passband limit. Quasi-elliptic function response and UWB operation are achieved. The simulated and measured results show an excellent agreement. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2470,2473, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24658 [source]

    Composite right/left-handed transmission line based on Koch fractal shape slot in the ground and UWB filter application

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2009
    Jian An
    Abstract A novel composite right/left-handed transmission line is presented which is synthesized by etching Koch fractal shape slot in the ground plane and series capacitive gap in the conductor strip. Unlike the structures loaded with complementary split ring resonators, the proposed structure can operate at very wideband and is used to design an ultra-wideband (UWB) filter. The UWB filter is fabricated and tested. The relative bandwidth of the ,10 dB return loss is 128% and the insertion loss is larger than ,1.5 dB except at high frequencies. The equivalent circuit model of the proposed structure is presented and the electrical parameters are also extracted. The circuit model results are compared with the simulation and measurement results which verify that not only the extracted parameters are exact but also the equivalent circuit model is reasonable. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2160,2163, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24553 [source]

    Compact UWB planar monopole antenna with band-notch function

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2009
    Li-Na Zhang
    Abstract A new band-notch ultrawideband (UWB) printed monopole antenna is proposed, where the band-notch characteristic is realized by introducing a microstrip feeder with a tuning stub. The simulation results agree well with the measured ones, showing that the proposed antenna provides an operating band ranging from 2.9 to 11.6 GHz, a notched band from 5.0 to 5.9 GHz, and a good omni-directional far-field radiation in the H-plane. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1908,1911, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24507 [source]

    A novel compact ultrawideband (UWB) bandpass filter using multiple-mode resonator

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2009
    D. Chen
    Abstract In this letter, a novel compact ultrawideband (UWB) bandpasss filter (BPF) using the proposed multiple-mode resonator (MMR) is presented. The MMR is composed of a conventional microstrip hairpin resonator of which the two arms are connected by a section of microstrip line and a short-circuited point located in the middle of the hairpin resonator. Its first three resonant modes can be utilized to construct the UWB band. The tapped feeding structure has been used to realize desired tight couplings for designing the UWB BPF. The filter has been investigated numerically and experimentally. Both the simulated and measured results show that the filter has good performance, such as compact size, low-insertion loss, small group delay variation, and improved out-of-band performances. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1662,1664, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24424 [source]

    A novel compact band-notched planar monopole antenna from 3 to 40 GHz

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2009
    F. Zhang
    Abstract A novel and compact ultra-wideband (UWB) microstrip-fed monopole antenna with frequency band notch function is presented in this study. Different from the conventional methods, a new method of inserting a lune-shaped disk into the annular structure to achieve a notched band is proposed in this letter. The center frequency of the notched band can be adjusted with ease by tuning the length of the lune-shaped disk. The designed antenna satisfies the voltage standing wave ratio (VSWR) requirement of less than 2.5 in the frequency between 3 and 40 GHz while showing the band rejection performance in the frequency band of 4.65 to 5.81 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1401,1403, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24377 [source]

    Ultra-wideband slot antenna with band-notch characteristics for wireless USB dongle applications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2009
    Deepti Das Krishna
    Abstract A compact ultra-wideband (UWB) printed slot antenna is described, suitable for integration with the printed circuit board (PCB) of a wireless, universal, serial-bus dongle. The design comprises of a near-rectangular slot fed by a coplanar waveguide (CPW) printed on a PCB of size 20 × 30 mm2. It has a large bandwidth covering the 3.1,10.6 GHz UWB band, with omnidirectional radiation patterns. Further, a notched band centered at 5.45 GHz wireless local area network bands is obtained within the wide bandwidth by inserting a narrow slot inside the tuning stub. Details of the antenna design are described, and the experimental results of the constructed prototype are presented. The time domain studies on the antenna shows a linear phase response throughout the band except at the notched frequency. The transient analysis of the antenna indicates very little pulse distortion confirming its suitability for high speed wireless connectivity. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1500,1504, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24385 [source]

    Design of dual-band antenna with U-shaped open stub for WLAN/UWB applications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009
    Jung N. Lee
    Abstract In this article, we have proposed a dual-band antenna with U-shaped open stub for wideband local area network (WLAN)/ultra wideband (UWB) applications. The designed dual-band antenna consists of two semicircle radiating patches, a rectangular slot separating the two semicircles, one step for impedance matching, and coplanar waveguide (CPW) feeding. Two kinds of prototypes (CPW-fed UWB antenna and the dual-band antenna with U-shaped open stub) are fabricated and measured. Parametric studies and radiation characteristics for the two antennas are presented. The designed antenna has the figure-of-eight radiation pattern, wide bandwidth, and negligible dispersion over the operating frequency band. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 284,289, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24033 [source]

    A compact ultra-wideband bandpass filter with WLAN notch band

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009
    Pai-Yi Hsiao
    Abstract A compact ultra-wideband (UWB) bandpass filter (BPF) with notch band is presented using a trilayer structure. The band elimination is essential for preventing the strong narrow band interference from the wireless local area networks within the allocated UWB spectrum. The sharp rejection of the unwanted band is introduced by adding a U-shape resonator on the middle layer. The design is not only realized theoretically but also verified by a full-wave electromagnetic simulation. The proposed UWB BPF is fabricated by an FR4 substrate material with the permittivity of 4.4 and the thickness of 0.8 mm. The total area is 8 mm × 6 mm. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 503,507, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24093 [source]

    Wideband cylindrical monopole antenna for multiband wireless applications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2009
    Joong-Chang Chun
    Abstract A wideband cylindrical monopole antenna is presented for multiple band applications. Wideband property of the proposed antenna is achieved by the additional resonance from a stepped base part and a convex ground plane. The measured ,10 dB impedance bandwidths are 1.74,3.06 and 5.59,10.62 GHz, which can cover various kinds of wireless services such as PCS (1.75,1.87 GHz), IMT-2000 (1.92,2.17 GHz), WiBro (2.3,2.39 GHz), WLAN (2.412,2.483 GHz, 5.725,5.825 GHz), DMB (2.63,2.655 GHz), and high-band UWB in Korea (7.2,10.2 GHz). © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 15,17, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23981 [source]

    Planar 4-element UWB antenna array and time domain characterization

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008
    Ying-Ying Yang
    Abstract In this article, a novel planar ultra-wideband (UWB) antenna array based on four identical UWB antenna elements for UWB applications is presented. The proposed antenna array yields an impedance bandwidth of 3.1,10.6 GHz with VSWR <2. Over the entire bandwidths, it has constant high gain, which is about 6.5,10.5 dBi, and a 60° 3-dB beamwidth is obtained within the operational band. A planar 2-element UWB antenna array and a band-notched 4-element UWB antenna array are also provided for references. Time domain descriptors of the proposed antenna array have been used to estimate short-range UWB signal transmission, propagation, and reception. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3118,3123, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23874 [source]

    A novel ultra-wideband monopole antenna with two symmetrical strips

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2008
    Hyo W. Song
    Abstract In this article, we have described a novel ultra-wideband (UWB) monopole antenna with two symmetrical strips for wireless UWB communications. The proposed antenna consists of a center monopole, two symmetrical strips having one step on the strip, and CPW feeding. Three techniques (one monopole and two strips, symmetrical structure, and step on the strip) are used to produce the multiple resonance and low dispersion. The proposed UWB antenna has an omnidirectional radiation pattern, UWB, compact size, almost flat gain and linear phase, and low cost. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2845,2848, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23838 [source]

    A dual-band rejected cross monopole antenna maintaining omnidirection radiation

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2008
    Wen-Shan Chen
    Abstract UWB cross semi-elliptic monopole antenna with a dual-band rejected characteristic is presented and experimentally studied. The proposed cross bevel-rectangular monopole antenna is embedded with four small h-shaped slots; it produces a design of dual-band rejected characteristics and maintains omnidirection radiation. This technique is suitable for creating multiwideband antenna or ultrawideband (UWB) antenna with dual-rejected band. And the proposed antenna with good omnidirection characteristic is also maintained. Details of the results for the proposed antenna are presented and discussed in this study. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2491,2493, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23712 [source]

    Synthesis of ultrawideband bandpass filter by multisection of commensurate stepped-impedance resonators

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2008
    Chun-Ping Chen
    Abstract A novel filter prototype composed of multisection of stepped impedance resonators (SIRs) is proposed to realize the ultra-wideband bandpass (UWB) filter. The relation between the modes number and stage number of resonators is first discussed, followed by the derivation of the corresponding Chebyshev filtering function. Furthermore, the equivalent circuit model of this new filter prototype is established based on the transmission-line theory for filter synthesis. As an example, a FCC UWB filter is synthesized with the proposed filter prototype to possess a passband from 3.1 to 10.6 GHz (fractional bandwidth is about 110%). The synthesized circuit model are further optimized by EM simulator, fabricated in microstrip line, and characterized by network analyzer. The good agreement between the measured and predicted frequency responses validates the effectiveness of newly proposed synthesis approach. In addition, the designed filter exhibits good characteristics of comparatively low insertion loss, quite sharp skirts, very flat group delay, and good stopband (especially in lower one) as well. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2635,2639, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23756 [source]

    Compact ultrawideband square slot antenna with an asymmetric protruding stub

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2008
    Jen-Yi Shiu
    Abstract A new compact ultra-wideband (UWB) square slot antenna fed by a coplanar waveguide (CPW) is proposed. A large impedance bandwidth of more than 13 GHz (2.8,16 GHz) was obtained by asymmetrically widening the tuning stub that is extended from the signal strip of the CPW into the square slot. The larger and smaller widened parts of the asymmetric tuning stub can be easily adjusted to achieve good impedance matching in the lower and upper regions, respectively, of the entire VSWR , 2 band. The simple design procedure along with reasonably agreed measured and simulated results is presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1776,1779, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23544 [source]

    Low cost ultra wideband amplifier in 0.35 ,m CMOS process

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2008
    Kuldip N. Modha
    Abstract A two stage ultra wideband (UWB) amplifier is presented. This amplifier incorporates multiple bandwidth enhancing techniques and is implemented in Austria micro systems (AMS) 0.35 ,m CMOS process technology. The amplifier consumes 39.5 mW of power, exhibits a maximum gain of 13 dB, has input and output reflections below ,9 and ,10 dB, respectively over a ,3 dB bandwidth of 4 GHz. The average measured noise figure is 6 dB and 1 dB compression point at 3 GHz is ,12 dBm. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1879,1881, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23525 [source]

    Design of a miniaturized planar antenna for FCC-UWB communication systems

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2008
    L. Lizzi
    Abstract In this letter, the design of a planar antenna compliant with FCC requirements for ultra-wideband (UWB) transmission systems is described. With reference to a planar geometry on a dielectric substrate, the shape of the antenna is described by means of a spline-based representation and it is determined by means of an optimization process aimed at finding the optimal descriptive parameters that allow to fit the user-defined electrical and dimensional requirements. The reliability and effectiveness of the antenna prototype are assessed through simulations as well as experimental measurements. © Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1975,1978, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23519 [source]