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A folded monopole antenna (FMA) with two different input impedances were investigated to develop an antenna that is robust to metal for applications in a space enclosed by metal objects. An antenna with a variable input impedance is required for improving its robustness to the metal. An FMA with a novel structure is proposed to control the input impedance using a simple configuration. The structure comprises six additional elements parallel to the FMA. However, the number is not limited to six. Some additional elements are electrically connected or disconnected depending on the requirement. Method of moment (MoM) and characteristics mode analysis (CMA) are used in the simulation. The MoM results demonstrate that the input impedance can be adjusted in a step‐wise manner based on the number of additional elements connected to the FMA. This result is similar to that of the input impedance of an FMA with different strip widths considering impedance step‐up ratios (SURs). Furthermore, the change in the antenna characteristics owing to the non‐connected additional elements is minimal. The CMA results reveal that the proposed antenna has the same operation mode as the FMA with different strip widths considering impedance SURs. [ABSTRACT FROM AUTHOR]

Abstract: In this article, a concise equivalent circuit model for top‐loaded folded monopole antenna (TLFMA) of low profile is presented. The TLFMA has one driven post and one shorting post, loaded with a circular conducting plate on the top, which can achieve a very low profile with a good radiation resistance. The equivalent circuit consists of two models, which are transmission‐line mode and antenna mode. The impedance of TLFMMA can be easily get from this equivalent circuit model. The accuracy of the presented equivalent circuit model has been verified by the simulation and measurement results. [ABSTRACT FROM AUTHOR]

Abstract: Two novel wideband balanced‐to‐unbalanced power dividers based on transmission lines and coupled lines are proposed in this article. Multifunction can be realized without cascading single devices with common mode suppression. The desired power divider configurations can be obtained using the even/odd‐mode characteristic impedance of the coupled lines and characteristic impedance of the transmission lines. A resistor in the middle of two single‐ended ports is used to realize isolation between output ports. Two prototypes of wideband balanced‐to‐unbalanced power dividers operating at 2.3 GHz with differential‐mode bandwidths of 79.6 and 134.1% are designed and fabricated. The theoretical and measured results are in good agreement and show good in‐band performances. [ABSTRACT FROM AUTHOR]

A circularly polarized (CP) Microstrip Yagi array antenna (MSYA) is designed in order to achieve high front-to-back ratio R(F/B) and high gain over wide range in the forward radiation space. A Wilkinson power divider owning two output ways with the same magnitude and different phase is used to feed the antenna. Parametric studies are carried out to investigate the effects of some key geometrical sizes on the antenna’s performance. A prototype of the antenna is fabricated, and good agreement between the measured results and the numerical simulations is observed. The overlap bandwidth of VSWR ≤ 1.5 and AR ≤ 3 dB is about 11%. The steering angle (α) between the peak gain direction and the broadside can achieve 35°, R(F/B) reaches 19 dB, and the gain at the front point (G0) is only 4.3 dB lower than the maximum gain (Gm). The antenna has a wide beamwidth CP radiation pattern over wide spatial range including 0° ≤ θ ≤ 90° in vertical plane and −35° ≤ φ ≤ 55° in horizontal plane. [ABSTRACT FROM AUTHOR]

A novel compact chipless RFID tag using spurline resonators is discussed in this paper. The detection of the tag's ID is using the spectral signature of a spurline resonator circuit. The tag has a data capacity of 8-bits in the range 2.38 to 4.04 GHz. The tag consists of a spurline multiresonating circuit and two cross polarized antennas. The prototype of the tag is fabricated on a substrate C-MET/LK4.3 of dielectric constant 4.3 and loss tangent 0.0018. The measured results show that group delay response can also be used to decode the tag's identity. [ABSTRACT FROM AUTHOR]

This study presents a multi-level optimization (MLO) method applied in particle swarm optimization (PSO) to solve a 3-objective optimization problem for an antenna array design consisting of two L-shaped folded monopole antennas (LFMAs) operating in the IEEE 802.11 b/g WLAN band (2400–2484 MHz). The method incorporates a simple concept whereby three sub-objective functions, representing the reflection coefficient S 11, the mutual coupling S 21, and the entire antenna volume of the LFMA array, are minimized one by one in the PSO to obtain an optimal LFMA array configuration that provides reduced size and higher antenna performance. The advantages of the proposed method, both in terms of deriving appropriate optimization results and reducing computational cost for the optimization problem, are demonstrated by comparing its performance with that of a conventional weighted aggregation (CWA) method, and a method using the concept of Pareto dominance (PD). The optimal LFMA array configuration obtained by the proposed method has a 10% resonant bandwidth (S 11 \le -10 dB for 2.32–2.57 GHz), S 21 reduced to less than -15 dB in this band, and an antenna volume that was markedly decreased, to 28.5% of that of the original design. [ABSTRACT FROM AUTHOR]

In this paper, a compact ultra wideband (UWB) monopole antenna with a band-notched characteristic is presented. The band-notched characteristic is achieved by inserting a U-shaped slot in the half elliptical ring radiating patch. The measured bandwidth of the designed antenna for |S11| ≤ -10 dB spans 3.1 GHz to 9.3 GHz with a notched band (|S11| > -10 dB) spanning 5.12 GHz to 5.99 GHz. A quasi-omnidirectional radiation pattern in the x-z plane and quasi-symmetrical radiation patterns in the x-y and y-z planes are obtained throughout the operating band. The antenna is suitable for UWB communication applications and also reduces the interference with wireless local area network (WLAN) systems. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated in this paper. [ABSTRACT FROM AUTHOR]

The theory and implementation of a new family of monopole antennas loaded with composite right/left handed (CRLH) unit cells are presented. The proposed antennas have a number of narrow bands that is twice the number of unit cells and one wide band that is centered around the monopole original frequency. The new operating frequencies are below the original one and they are controlled by the unit cell dispersion relation. The proposed antennas occupy the same Chu sphere as the original monopole, all the operating frequencies have omni-directional radiation patterns, and matching is better than -10 dB. Three antennas are realized; the first is loaded with one distributed CRLH unit cell, the second is loaded with lumped components CRLH unit cell, and the third is loaded with two CRLH unit cells. All proposed antennas are fabricated and measured. Measurements and EM simulations confirm the proposed theory. [ABSTRACT FROM PUBLISHER]

A novel broadband design of planar arc-shaped monopole antenna with a rectangular parasitic patch for UWB system is proposed. With the use of rectangular parasitic patch, multi resonant modes are excited to meet the specifications of UWB system. Moreover, the obtained impedance bandwidth across the operating band can reach about 10.25 GHz. The measured peak gains and radiation efficiencies are about 1.2–5.3 dBi and 85–91% across the operating band, respectively, with nearly omni-directional pattern in the XY-plane. [ABSTRACT FROM PUBLISHER]

In this paper, we present an antenna design for telemedicine applications operating in the Industrial Scientific Medical (ISM) 2.4 GHz band. The design is based on a printed monopole antenna integrated with an artificial magnetic conductor (AMC) ground plane. The AMC ground plane is utilized to isolate the user's body from undesired electromagnetic radiation in addition to eliminating the antenna's impedance mismatch caused by the proximity to human tissues. Moreover, specific absorption rate (SAR) is analyzed based on a numerical human body model (HUGO) to assess the design feasibility. Results show that the radiation characteristics, impedance matching, and SAR values of the proposed design are significantly improved compared with conventional antennas. [ABSTRACT FROM AUTHOR]

In this paper, we propose several array topologies to achieve good power-combining characteristics for the open slot antenna. By utilizing an appropriate feeding structure and injecting in- phase or out-of-phase signals, power-combining radiation patterns can be derived. Simulated surface current distributions of several antenna structures are presented to explain radiation mechanism. From the results of radiation performance, the advantages of gain enhancement and pattern reconfiguration are shown. By varying the phase difference of two injected signals of the open slot antenna array, two-dimensional beam-scanning radiation patterns are successfully demonstrated. [ABSTRACT FROM AUTHOR]

A novel compact dual-band MIMO antenna with high port isolation is proposed. The proposed antenna is basically composed of two folded monopoles and designed to operate at 2.4/5.6 GHz. The high isolation is achieved by introducing two transmission lines on the top surface of the substrate and etching two slots on the ground. The measured isolation higher than 15 dB is in 2.34-2.50 and 5.45-5.75 GHz bands, with the measured return loss higher than 10 dB. The predicted results are compared with the measured data, and good agreement is found. [ABSTRACT FROM AUTHOR]

A novel wide-band printed antenna, named forked shape monopole antenna (FSMA), is proposed. The forked shape line structure is introduced to create a capacitive coupling effect to reduce the antenna size and enhance the impedance bandwidth. The proposed antenna is to be applied in a compact USB dongle. And it is designed for the reception of the digital video broadcasting (DVB) signal in the 470 \sim 860 MHz frequency band. In addition to the DVB application, the upper band limit of the FSMA even can be extended from 860 MHz to 1142 MHz, suitable for use in the Global System for Mobil Communication (GSM850/900). By employing the branched-line and forked shape configurations, an antenna with 86% impedance bandwidth (SWR<2.5) is provided. A prototype of the FSMA was constructed and demonstrated. Measured and simulated results for the FSMA alone and with real application on a laptop computer are obtained. [ABSTRACT FROM PUBLISHER]

Novel integrated planar monopole antennas with various microstrip resonators are presented. The proposed integrated antennas consist of wideband planar monopole antennas and electromagnetically coupled microstrip resonators producing band-notched characteristics. Various types of microstrip resonators such as open-circuited line resonator, short-circuited line resonator, closed-loop resonator and open-loop resonator are described. The proposed designs are suitable for wideband antennas with narrowband interferer rejection characteristic or multi-band antennas. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a wideband planar surface wave antenna for the 5GHz wireless local area network (WLAN) router applications is proposed. The antenna is excited by a center-fed circular patch with an annular ring patch (ARP) and a thin dielectric slab with periodic circular patches (PCPs) is loaded on the circular patch radiator. A prototype of the 0.3-mm-thick antenna was constructed and tested to evaluate its suitability for reducing router thickness. The impedance bandwidth of the antenna was 23.6% (5.7–7.1GHz) and its average gain was 5.91dB. The radiation pattern of the antenna was nearly omnidirectional. [Copyright &y& Elsevier]

In this paper, a broadband compact folded monopole antenna is proposed for mobile applications. The antenna is a simple structure of a folded rectangular patch with a slit, which occupies only a small space of 7 × 12 × 4 mm3 (0.054λL × 0.092λL × 0.031λL at lower frequency edge of 2.3 GHz) on the top of no-ground portion of the substrate. The proposed antenna achieves a 10- dB impedance bandwidth of 49.2% ranging from 2.3 GHz to 3.8 GHz, which can cover the 2.4 GHz WLAN (2.4–2.4835 GHz) and WiMAX (2.3–2.4/2.495–2.69/3.4–3.6 GHz) operational bands. The low profile structure and broadband operation make the antenna a promising candidate for applications in mobile phones. [ABSTRACT FROM AUTHOR]

This article presents a new multiband antenna for handheld devices. The antenna consists of three branches of folded monopoles, and it is designed to operate at most application bands used currently, such as GSM 850/900/1800/1900, UMTS2100, and WLAN 5GHz. The simulated and measured results validate the proposed design. The proposed antenna has better performances than other embedded antenna designs of the same maximum dimension. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 421–425, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24930 [ABSTRACT FROM AUTHOR]

An internal clamshell mobile phone antenna using a simple dual-band folded monopole slot for covering penta bands of WWAN operation is presented. The folded monopole slot has a length of about 60 mm only and is easily printed on the top portion (10 x 40 mm2 ) of the main circuit board and suitable to be placed at the hinge of the clamshell mobile phone. By further placing the connecting strip between the two ground planes to be in the vicinity of the open end of the monopole slot, the two (main and upper) ground planes of the clamshell mobile phone can also be excited to be efficient radiators (dipole-like chassis or groundplane modes excited through the strong electric field occurred at the slot's open end). By incorporating the resonant modes contributed from both the monopole slot and the two ground planes, two wide bands at about 900 and 1900 MHz are formed, which easily cover GSM850/900/1800/1900/UMTS operation. Owing to the additional resonant modes contributed by the two ground planes, the use of a simple folded monopole slot is sufficient to cover penta-bandWWAN operation. This leads to compact size for the proposed clamshell mobile phone antenna. Details of the proposed antenna, including its SAR results, are presented. [ABSTRACT FROM AUTHOR]

This paper presents the analysis, design and measurement of novel, low-profile, small-footprint folded monopoles employing planar metamaterial phase-shifting lines. These lines are composed of fully-printed spiral elements, that are inductively coupled and hence exhibit an effective high-ia property. An equivalent circuit for the proposed structure is presented, validating the operating principles of the antenna and the metamaterial line. The impact of the antenna profile and the ground plane size on the antenna performance is investigated using accurate full-wave simulations. A )t/9 antenna prototype, designed to operate at 2.36 GHz, is fabricated and tested on both electrically large and small ground planes, achieving on average 80% radiation efficiency, 5% (110 MHz) and 2.5% (55 MHz) -10 dB measured bandwidths, respectively, and fully omnidirectional, vertically polarized, monopole-type radiation patterns. [ABSTRACT FROM AUTHOR]

In this article, a compact ultra-wideband monopole antenna with dual band-notched characteristic is proposed, in which the C-shaped slot creates one band-notch at 3.5 GHz, and the pair of inverted-L-shaped slots produce another band-notch at 5.8 GHz. Simulated and measured results show that the operating frequency band (VSWR < 2) of the proposed antenna is from 2.7 to 11.5 GHz, with the dual bands of 3.3–3.7 GHz and 5.5–6.4 GHz notched. By changing the lengths of the C-shaped slot and the pair of inverted-L-shaped slots, the central frequencies of the dual notched bands can be adjusted easily. [ABSTRACT FROM AUTHOR]

The authors have investigated radioelectrical performances of monopole antennas fabricated from transparent conducting films. Ultrathin copper layer, Indium Tin Oxide (ITO) film and ITO/Cu/ITO multilayer have been deposited by r.f. sputtering. For each sample, sheet resistance, optical transparency, radioelectrical performances have been evaluated and discussed. This research shows that multilayer technology is suitable for UHF band applications. [ABSTRACT FROM AUTHOR]

An antenna that is used at both the transmit and receive end of the same dispersionless communications link should have a time domain response that looks like a half-derivative on transmit, at least over the frequency range of interest. Time domain reciprocity then dictates that the antenna will compensate for this half-derivative when used as the receiver, producing a flat channel response in the frequency domain. The desired waveform is produced by a pulsed infinite line source. An antenna concept based on a partially focused transverse electromagnetic horn might be able to mimic this performance over a finite frequency range. [ABSTRACT FROM AUTHOR]

We propose a stochastic model for multiple-input multiple- output (MIMO) communication systems based on the eigendecomposition of the spatial correlation matrix. It is shown that the channel matrix can be well modeled by the superposition of the spatial eigenmodes experiencing independent Nakagami-m fading. The proposed scheme is also compared with the existing correlation-based models using the data obtained from an indoor measurement campaign so that its performance is assessed in depth. [ABSTRACT FROM AUTHOR]

The idea of so-called macromodels is applied to problems of computational electromagnetics involving integral-equation/method-of-moments formulations. It is shown that with the use of equivalence principles, it is possible to exclude a part of the problem, calculate its wideband response without an a priori knowledge of the excitations, and then efficiently combine the result into the original situation. The idea is validated using examples involving slot-excited dielectric resonator antennas. [ABSTRACT FROM AUTHOR]

The performance of radar target identification using the natural E-Pulse technique is significantly degraded if the sampling rates of the target response and the E-Pulse filter are ignored. In this work, improved sampling procedures over that previously reported by Antony and Shuley (Electron. Lett., vol. 40) in 2004 are proposed. Numerical results demonstrate that the proposed procedures significantly improve the target identification performance. [ABSTRACT FROM AUTHOR]

We indicate that the two-dimensional (2-D) direction-of-arrival (DOA) estimation method proposed by N. Tayem et at. has an error in the pair matching between the azimuth and elevation angle estimates. A feasible solution for pair matching is proposed. [ABSTRACT FROM AUTHOR]

A wideband single chip inductor-loaded coplanar waveguide (CPW)-fed inductive slot antenna is proposed and experimentally studied in this paper. In order to have bandwidth broadened and dimensions controlled as well, an inductor with optimal value is shunt at one far end of the inductive slot antenna to help excite an additional lower resonance point. Moreover, the bandwidth is further widened by enlarging the over-the-slot ground height. With both the optimal chip inductor and ground height values, a 10 dB return loss bandwidth of (34.5%, 1756 MHz) centered at 5083 MHz is achieved, which is, in percentage, 3.7 times the (9.3%, 531 MHZ) bandwidth of the 5666 MHz stand-alone CPW-fed inductive slot antenna. [ABSTRACT FROM AUTHOR]

A broadband plate antenna operating at a frequency range of 3-12 GHz is proposed for ultrawideband (UWB) applications. The plate antenna consists of a shorting wall attached to the radiator. The radiator is excited by a parasitic L-shaped plate connected to a feeding probe. The vertical section of the L-shaped feeding plate is separated at a distance from the shorting wall. With the electromagnetic coupling between the feeding plate and the radiator, a broad impedance bandwidth is achieved. Also, the antenna with reduced size is able to achieve the stable radiation performance with gain greater than 4 dBi across the entire UWB band. [ABSTRACT FROM AUTHOR]

The design of a dual-polarization stacked patch antenna to be used in GSM-UMTS base station arrays is presented. The patch shows a high matching level in a broadband and isolation between elements that make it a suitable radiating element for base station arrays. Moreover, the most relevant achievement of this element is the isolation between the two polarization ports of the same element in the antenna operating bandwidth. A prototype has been manufactured and measured. The measurements, that match the design objectives, are also presented. [ABSTRACT FROM AUTHOR]

A comprehensive and integrative overview (excluding ultrawideband measurements) is given of all the empirical data available from the open literature on various temporal properties of the indoor radiowave communication channel. The concerned frequency range spans over 0.8-8 GHz. Originally, these data were presented in about 70 papers in various journals, at diverse conferences, and in different books. Herein overviewed are the multipaths' amplitude versus arrival delay, the probability of multipath arrival versus arrival delay, the multipath amplitude's temporal correlation, the power delay profile and associated time dispersion parameters (e.g., the RMS delay spread and the mean delay), the coherence bandwidth, and empirically "tuned" tapped-delayline models. Supported by the present authors' new analysis, this paper discusses how these channel-fading metrics depend on the indoor radiowave propagation channel's various properties, (e.g., the physical environment, the floor layout, the construction materials, the furnishing's locations and electromagnetic properties) as well as the transmitted signal's carrier-frequency, the transmitting-antenna's location, the receiving-antenna's location, and the receiver's detection amplitude threshold. [ABSTRACT FROM AUTHOR]

A previously published guideline for MIMO antenna arrays is refuted. The influence of radiation efficiency on diversity gain and MIMO capacity of wireless communications systems is investigated through simulations and measurements using a reverberation chamber. Integrated antennas on a portable device have efficiencies low enough to disallow typical inter-element correlation assumptions. Both diversity gain and MIMO capacity depend on the number of antennas, SNR and efficiency in a complex way. When the efficiency of antennas is considered, certain system capacity losses are predicted and measured. These losses may be recovered through using more receive elements than commonly recommended or through the addition of a smaller number of more efficient antennas. [ABSTRACT FROM AUTHOR]

A design is proposed of a multiresonant monopole antenna for a personal wireless communication handset. Multiresonant operation is achieved through the use of a bent tuning stub, a shorting strip line, a U-shaped slit and the addition of a narrow resonant slit to the main radiator. The first resonant frequency is determined by the main radiator of the proposed antenna, and the second resonant frequency is controlled by the length of the bent tuning stub. The third resonant frequency is generated by adding a narrow resonant slit to the perimeter of the main radiator. The three resonant frequencies of the designed antenna can be independently controlled by tuning the length of the individual elements of the proposed antenna. The measurement shows the intended four wireless communication services: Global System for Mobile communication (GSM900), Digital Communication System (DCS1800), US-Personal Communication System (US-PCS), and Satellite-Digital Multimedia Broadcasting (S-DMB). The proposed antenna is small enough to be built into a practical wireless mobile handset. The parameters determining the antenna's multiresonant characteristics are analyzed, and experimental results of the constructed prototype are presented and discussed. [ABSTRACT FROM AUTHOR]

This study theoretically analyses the transmission performance of UWB antennas and presents a design methodology for improving the transmission performance of printed monopoles. Using this methodology, a modified circular monopole are proposed and analyzed as the design example. Both measured and simulated results are provided and discussed for verifying the validity of proposed design methodology. In a typical lab environment, the deleterious multi-path transmission effects on the transfer function of the example antenna pair were observed and discussed. This optimization methodology would not bring any size or cost increase to the printed monopoles, and the improvement of transmission performance is quite discernible, which appears to be a significant improvement over printed UWB monopoles. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1285–1289, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23336 [ABSTRACT FROM AUTHOR]

In this paper, two new types of fractal monopole antennas named Penta-Gasket-Khoch (PGK) and Complementary-Penta-Gasket-Khoch (CPGK) are introduced. My designs have achieved a good input impedance match throughout the pass band (2–20 GHz), but some occasional irregular small mismatch exists. These antennas are suitable for applications in picocell environments for the operating bands of ICMS, UMTS, Bluetooth, WLAN and HIPERLAN systems. Further optimization and some manufacturing aspects have been considered. [ABSTRACT FROM AUTHOR]

This paper presents the design equations for lower band-edge frequency for all the regular shapes of printed monopole antennas with various feed positions. The length of the feed transmission line is a critical design parameter of these monopole antennas. Design curves for the length of the feed transmission line for various lower band-edge frequencies for all these regular shaped monopoles have been generated. A systematic study has been presented to explain the ultra-wide bandwidth obtained from these antennas with an example of elliptical monopole antenna. [ABSTRACT FROM AUTHOR]

A printed ultra wideband (UWB) monopole antenna is proposed for applications on stepped frequency continuous wave (SFCW) ground penetrating radar (GPR) within a frequency range of 100-1000 MHz. The proposed antenna consists of a hexagonal strip line with resistive loading and a rectangular slot that is added to the ground plane side of the printed antenna implemented on FR4 epoxy materials. The resistive loading at the hexagonal monopole is effective to increase bandwidth in the higher frequency region, while the rectangular slot is used to improve bandwidth characteristic in the lower frequency region. This paper investigates the characteristic improvement in the lower frequency region by applying a parametric study on the rectangular slot that is added at the ground plane side of the UWB monopole antenna. Computer simulation was conducted and measurements were carried out to validate the result. [ABSTRACT FROM AUTHOR]

A two-element, planar Yagi antenna with closely spaced elements is reported. Multiple folding in the driver is used to boost up the low radiation resistance due to the close spacing between the driver and the director. The antenna dimensions are first optimized in wire form and then transferred into a printed version on PET film. A prototype planar monopole Yagi is built and measured at 1 GHz. The maximum realized gain of the antenna on 50-μm PET film is measured to be 9.56 dB. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2106–2109, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22660 [ABSTRACT FROM AUTHOR]

We propose a new band-notched folded strip monopole antenna for ultrawideband applications. This antenna is composed of a forked-shape radiator and a 50 Ω microstrip line. To achieve band-rejected filtering property at the WLAN bands, the forked-shape strips are folded back and result in a pair of coupled lines on the radiator. The length and gap width of the coupled lines primarily determine the notched frequency of the antenna. Based on the band-notched resonance, an equivalent circuit model is proposed for the antenna and the calculated antenna input admittance agrees with the full-wave simulation data. With the help of the dimensionless normalized antenna transfer function, the radiation characteristics are investigated thoroughly. The transmission responses of a transceiving antenna system and their corresponding transient analysis are discussed at the end of this paper. [ABSTRACT FROM AUTHOR]

A low-profile folded-monopole antenna with high radiation efficiency is presented, consisting of only two unbalanced composite right-/left-handed transmission line unit cells. An even-odd mode analysis shows that the even mode necessary to realise the folded-monopole effect prevails at the zeroth-order frequency, determined by the shunt resonance of the unbalanced unit cell. Loading a spiral inductor in each unit cell's top patch can keep the antenna in a low profile at a relatively low self-resonant frequency, and a substantial increase in the radiation resistance is generated according to the multiple folded monopole theory, enabling the antenna to be well matched to 50 Ω without adopting any external matching network. A prototype antenna of λ/10×λ/20×λ/10, operative at 3.0 GHz, has been fabricated and measured, which can achieve radiation efficiency of above 90% and fully omnidirectional monopole-type radiation pattern. [ABSTRACT FROM AUTHOR]

The simple printed monopole antenna for dual-band operation with tunability is proposed. It uses the ground shorted inset sleeve of which the length is controlled. This type of antenna can easily produce dual-band characteristics without any additional metal strips or radiating elements. The omni-directional radiation patterns at both design frequencies are similar to those of a conventional monopole. Details of the proposed monopole design and experimental results are demonstrated in this letter. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1731–1733, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25308 [ABSTRACT FROM AUTHOR]

A compact and simple monopole antenna with CPW-fed structure is proposed for application in dual-band WLAN systems. The proposed antenna, which resembles the shape of the letter “e”, has a compact size of only 27 × 18 × 1.6 mm3 including the ground. By fabricated and measured, the proposed antenna covers both 2.4 GHz (2.4–2.484 GHz) and 5 GHz (5.15–5.825 GHz) bands and provides good radiation characteristics and antenna gains for the operating bands. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1377–1379, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24339 [ABSTRACT FROM AUTHOR]

A printed circular-ring monopole antenna with band-notched feature for UWB application has been presented and investigated. The band-notched characteristic is achieved by inserting a circular arc slot on the ring radiator. Experimental results show that the proposed antenna meets the requirement of wide-working bandwidth of 3.1–10.6 GHz with VSWR <2, while avoiding the interference with the 5 GHz WLAN band. The transfer functions of the antenna systems are given experimentally, and the parametric studies are performed numerically in this article. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1882–1884, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23524 [ABSTRACT FROM AUTHOR]

An effective frequency domain full-wave approach is proposed for the simulation of time modulated (TM) linear arrays with variable aperture size (VAS) time schemes. The full-wave simulation of the TM linear arrays is fulfilled by combination of the frequency domain full-wave simulation results of the corresponding regular linear arrays at multiples of the modulation frequency. Numerical simulation results of two TM linear arrays with VAS time schemes are presented and are compared with reported measurement results, and close agreement is obtained through comparison. [ABSTRACT FROM AUTHOR]

A single-fed circularly polarized stacked patch antenna is proposed to cover all GPS bands, including the E5a/E5b band for the Galileo system. The small aperture size (λ8 at 1176 MHz, the L5 band) makes this antenna attractive for small GPS arrays. Also, in contrast to previous GPS antennas, the presented design uses a single feed for circular polarization. In this paper, we present the design procedures and performance of the designed GPS antenna and discuss issues relating to coupling between array elements. Modifications to reduce coupling are then presented. [ABSTRACT FROM AUTHOR]

A novel broadband multi-T-shaped monopole antenna is presented. The proposed antenna has a broadband impedance bandwidth of 32.9%, which covers PCS, UMTS, WiBro, and WLAN bands. For frequencies over the operating bands, the proposed antenna displays omni-directional radiation patterns. The proposed antenna has compact dimensions of 14 mm × 14 mm. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1251–1253, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23355 [ABSTRACT FROM AUTHOR]

A miniaturised broadband top-loaded planar monopole (TLPM) antenna with binary-encoded sleeves is proposed. The antenna consists of a TLPM with an embedded artificial transmission line to reduce the operating frequency. To broaden the operating bandwidth of the proposed miniaturised monopole antenna, the binary-encoded sleeves are utilised and optimised using a genetic algorithm. A prototype of the proposed antenna is fabricated and tested. The measured -10 dB reflection coefficient bandwidth is 800-1265 MHz (45.04%). A peak gain of 4.11 dBi and consistent radiation patterns are achieved within the operating frequency band. [ABSTRACT FROM AUTHOR]

Proposed is a low-power switch with a folded waveguide arms layout and suspended ridge structures. An extremely low power consumption of 0.40 mW / MZI and a high extinction ratio of more than 30 dB for TE polarisation were achieved. [ABSTRACT FROM AUTHOR]

A novel ultra-wideband printed monopole antenna with a band-notch characteristic and stable omnidirectional radiation is presented. The antenna design adopts a bevelled square patch as a monopole, a double-feed technique and a microstrip feeder embedded with an inverted U-shaped slot. Good agreement between simulation and experiment shows that the proposed antenna achieves an impedance bandwidth of 3.05–5.15 and 6.02–10.84 GHz for VSWR≤2, a stable omnidirectional radiation and a low cross-polarisation level. [ABSTRACT FROM AUTHOR]