M.Y.W. Chia

Bio: M.Y.W. Chia is an academic researcher from Institute for Infocomm Research Singapore. The author has contributed to research in topics: Microstrip antenna & Balun. The author has an hindex of 21, co-authored 41 publications receiving 2178 citations. Previous affiliations of M.Y.W. Chia include National University of Singapore & Agency for Science, Technology and Research.

Considerations for source pulses and antennas in UWB radio systems

Abstract: This paper addresses two vital design considerations in ultrawide-band radio systems. One is that radiated power density spectrum shaping must comply with certain emission limit mask for coexistence with other electronic systems. Another is that the design of source pulses and transmitting/receiving antennas should be optimal for the performance of overall systems. The design of source pulses and transmitting/receiving antennas under the two considerations is discussed. First, the characteristics of transmitting/receiving antenna systems are described by a system transfer function. Then, the design of source pulses and transmitting antennas are studied based on the considerations for emission limits. Finally, the design of transmitting and receiving antennas are investigated in terms of pulse fidelity and system transmission efficiency. In the studies, thin wire dipoles with narrow bandwidths and planar dipoles with broad bandwidths are exemplified.

Broadband Planar Antennas: Design and Applications

Abstract: Foreword. Preface. Acknowledgements. 1 Planar Radiators. 1.1 Introduction. 1.2 Bandwidth Definitions. 1.2.1 Impedance Bandwidth. 1.2.2 Pattern Bandwidth. 1.2.3 Polarization or Axial-ratio Bandwidth. 1.2.4 Summary. 1.3 Planar Antennas. 1.3.1 Suspended Plate Antennas. 1.3.2 Bent Plate Antennas. 1.4 Overview of this Book. References. 2 Broadband Microstrip Patch Antennas. 2.1 Introduction. 2.2 Important Features of Microstrip Patch Antennas. 2.2.1 Patch Shapes. 2.2.2 Substrates. 2.2.3 Feeding Structures. 2.2.4 Example: Rectangular Microstrip Patch Antennas. 2.3 Broadband Techniques. 2.3.1 Lowering the Q. 2.3.2 Using an Impedance Matching Network. 2.3.3 Case Study: Microstrip Patch Antenna with Impedance Matching Stub. 2.3.4 Introducing Multiple Resonances. 2.3.5 Case Study: Microstrip Patch Antenna with Stacked Elements. References. 3 Broadband Suspended Plate Antennas. 3.1 Introduction. 3.2 Techniques to Broaden Impedance Bandwidth. 3.2.1 Capacitive Load. 3.2.2 Slotted Plates. 3.2.3 Case Study: SPA with an -shaped Slot. 3.2.4 Electromagnetic Coupling. 3.2.5 Nonplanar Plates. 3.2.6 Vertical Feed Sheet. 3.3 Techniques to Enhance Radiation Performance. 3.3.1 Radiation Characteristics of SPAs. 3.3.2 SPA with Dual Feed Probes. 3.3.3 Case Study: Center-concaved SPA with Dual Feed Probes. 3.3.4 SPA with Half-wavelength Probe-fed Strip. 3.3.5 SPA with Probe-fed Center Slot. 3.3.6 Case Study: Center-fed SPA with Double L-shaped Probes. 3.3.7 SPA with Slots and Shorting Strips. 3.4 Arrays with Suspended Plate Elements. 3.4.1 Mutual Coupling between Two Suspended Plate Elements. 3.4.2 Reduced-size Array above Double-tiered Ground Plane. References. 4 Planar Inverted-L/F Antennas. 4.1 Introduction. 4.2 The Inverted-L/F Antenna. 4.3 Broadband Planar Inverted-F/L Antenna. 4.3.1 Planar Inverted-F Antenna. 4.3.2 Planar Inverted-L Antenna. 4.4 Case Studies. 4.4.1 Handset Antennas. 4.4.2 Laptop Computer Antennas. References. 5 Planar Monopole Antennas and Ultra-wideband Applications. 5.1 Introduction. 5.2 Planar Monopole Antenna. 5.2.1 Planar Bi-conical Structure. 5.2.2 Planar Monopoles. 5.2.3 Roll Monopoles. 5.2.4 EMC Feeding Methods. 5.3 Planar Antennas for UWB Applications. 5.3.1 Ultra-wideband Technology. 5.3.2 Considerations for UWB Antennas and Source Pulses. 5.3.3 Planar UWB Antenna and Assessment. 5.4 Case Studies. 5.4.1 Planar UWB Antenna Printed on a PCB. 5.4.2 Planar UWB Antenna Embedded into a Laptop Computer. 5.4.3 Planar Directional UWB Antenna. References. Index

A new wide-band planar balun on a single-layer PCB

Abstract: A new wide-band microstrip balun implemented on a single-layer printed circuit board (PCB) is presented in this letter. The proposed planar balun consists of a wide-band Wilkinson power divider and a noncoupled-line broad-band 180/spl deg/ phase shifter. To demonstrate the design methodology, one prototype is realized. The new design was simulated and validated by the measurement. Measured results show that 10-dB return loss of the unbalanced port has been achieved across the bandwidth from 1.7 GHz to 3.3 GHz, or 64%. Within the operation band, the measured return losses for both the two balanced ports are better than -10 dB, and the balanced ports isolation is below -1.5 dB. The measured amplitude and phase imbalance between the two balanced ports are within 0.3 dB and /spl plusmn/5/spl deg/, respectively, over the operating frequency band.

Near-Field Source Localization via Symmetric Subarrays

Abstract: We propose a near-field source localization algorithm with one-dimensional (1-D) search via symmetric subarrays. By dividing the uniform linear array (ULA) into two symmetric subarrays, the steering vectors of the subarrays yield the 1-D (only bearing-related) property of rotational invariance in signal subspace, which allows for the bearing estimation using the generalized far-field ESPRIT. With the estimated bearing, the range estimation of each source is consequently obtained by defining the 1-D MUSIC spectrum. This algorithm transforms the two-dimensional search involved in the parameter estimation to a 1-D search, and it does not require high-order statistics computation in contrast with the traditional near-field high-order ESPRIT algorithm

Miniature built-in multiband antennas for mobile handsets

Abstract: In this paper, we propose a new design for built-in handset antennas in that metal strips as additional resonators are directly connected with a feed strip. With the new design scheme, a quad-band antenna for covering GSM900, DCS1800, PCS1900, and UMTS2000 bands and a five-band antenna for covering GSM900, DCS1800, PCS1900, UMTS2000, and ISM2450 bands for use in mobile built-in handsets are experimentally carried out. Compared with the parasitic form with a shorted strip placed away from the main radiator in the open literature, the size of the proposed antennas can be reduced by an order of 10/spl sim/20%, which is desirable since the size of mobile phones is becoming smaller according to consumer preferences. Moreover, the impedance matching for each band of the new antennas becomes easy. The new quad-band and five-band built-in handset antennas are developed within the limits of a 36/spl times/16/spl times/8 mm/sup 3/ volume. The antennas are also analyzed using the finite-difference time-domain technique. A good agreement is achieved between measurement and simulation.

Study of a printed circular disc monopole antenna for UWB systems

Abstract: This paper presents a study of a novel monopole antenna for ultrawide-band (UWB) applications. Printed on a dielectric substrate and fed by a 50 /spl Omega/ microstrip line, a planar circular disc monopole has been demonstrated to provide an ultra wide 10 dB return loss bandwidth with satisfactory radiation properties. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated. A good agreement is achieved between the simulation and the experiment. In addition, the time domain performance of the proposed antenna is also evaluated in simulations.

Study and Reduction of the Mutual Coupling Between Two Mobile Phone PIFAs Operating in the DCS1800 and UMTS Bands

Abstract: Several solutions are presented to reduce the mutual coupling between two planar inverted-F antennas (PIFAs) working in close radiocommunication standards and positioned on a finite-sized ground plane modeling the printed circuit board (PCB) of a typical mobile phone. First, the two PIFAs are designed on separate PCBs to, respectively, operate in the DCS1800 and UMTS bands. In a second step, they are associated on the top edge of the same PCB. Realistic arrangements are then theoretically and experimentally studied. Finally, several solutions are investigated to maximize the isolation. They consist in inserting a suspended line between the PIFAs' feedings and/or shorting points. All along this paper, several prototypes are fabricated and their performances measured to validate the obtained IE3D moment method-based simulation results

Small Printed Ultrawideband Antenna With Reduced Ground Plane Effect

Abstract: A small printed antenna is described with a reduced ground-plane effect for ultrawideband (UWB) applications. The radiator and ground plane of the antenna are etched onto a piece of printed circuit board (PCB) with an overall size of 25mmtimes25 mmtimes1.5 mm. A notch is cut from the radiator while a strip is asymmetrically attached to the radiator. The simulation and measurement show that the miniaturized antenna achieves a broad operating bandwidth of 2.9-11.6 GHz for a 10-dB return loss. In particular, the ground-plane effect on impedance performance is greatly reduced by cutting the notch from the radiator because the electric currents on the ground plane are significantly suppressed at the lower edge operating frequencies. The antenna features three-dimensional omni-directional radiation with high radiation efficiency of 79%-95% across the UWB bandwidth. In addition, a parametric study of the geometric and electric parameters of the proposed antenna will be able to provide antenna engineers with more design information

Composite right/left-handed transmission line based compact resonant antennas for RF module integration

Abstract: Several electrically small resonant antennas employing the composite right/left-handed transmission line (CRLH-TL) are presented for integration with portable RF modules. The proposed antenna designs are based on the unique property of anti-parallel phase and group velocity of the CRLH-TL at its fundamental mode. In this mode, the propagation constant increases as the frequency decreases, therefore, a small guided wavelength can be obtained at a lower frequency to provide the small lambdag/2 resonant length used to realize a compact antenna design. Furthermore, the physical size and the operational frequency of the antenna depend on the unit cell size and the equivalent transmission line model parameters of the CRLH-TL, including series inductance, series capacitance, shunt inductance and shunt capacitance. Optimization of these parameters as well as miniaturization techniques of the physical size of unit cell is investigated. A four unit-cell resonant antenna is designed and tested at 1.06 GHz. The length, width and height of the proposed antenna are 1/19lambda0, 1/23lambda0 and 1/83lambda0, respectively. In addition, a compact antenna using a 2-D three by three mushroom like unit cell arrangement is developed at 1.17 GHz, showing that an increased gain of 0.6 dB and higher radiation efficiency can be achieved over the first prototype antenna. The same design is applied in the development of a circularly polarized antenna operating at 2.46 GHz. A 116deg beamwidth with axial ratio better than 3 dB is observed. The physical size of the proposed mushroom type small antenna and the circularly polarized antenna is 1/14lambda0 by 1/14lambda0 by 1/39lambda0 and 1/10lambda0 by 1/10lambda 0 by 1/36lambda0, respectively

Considerations for source pulses and antennas in UWB radio systems

Abstract: This paper addresses two vital design considerations in ultrawide-band radio systems. One is that radiated power density spectrum shaping must comply with certain emission limit mask for coexistence with other electronic systems. Another is that the design of source pulses and transmitting/receiving antennas should be optimal for the performance of overall systems. The design of source pulses and transmitting/receiving antennas under the two considerations is discussed. First, the characteristics of transmitting/receiving antenna systems are described by a system transfer function. Then, the design of source pulses and transmitting antennas are studied based on the considerations for emission limits. Finally, the design of transmitting and receiving antennas are investigated in terms of pulse fidelity and system transmission efficiency. In the studies, thin wire dipoles with narrow bandwidths and planar dipoles with broad bandwidths are exemplified.