Jean-Fu Kiang

Bio: Jean-Fu Kiang is an academic researcher from National Taiwan University. The author has contributed to research in topics: Microstrip & Dielectric resonator antenna. The author has an hindex of 21, co-authored 214 publications receiving 1777 citations. Previous affiliations of Jean-Fu Kiang include Dayeh University & Massachusetts Institute of Technology.

Wideband dielectric resonator antenna

Abstract: An antenna comprises a substrate, a feed conductor, a ground layer, a resonator and a short-circuited element. The substrate comprises a first surface and a second surface. The feed conductor is formed on the first surface. The ground layer is formed on the second surface, comprising an aperture. The resonator is disposed on the ground layer, comprising a body and a notch, the notch is formed on a first side of the body, wherein the first side is perpendicular to the ground layer. The short-circuited element is disposed on the first side connecting the ground layer.

Dual-Band Circularly Polarized Cavity-Backed Annular Slot Antenna for GPS Receiver

Abstract: A circularly polarized (CP) cavity-backed annular slot antenna for GPS receiver is designed to operate in both the L1 and L2 bands of the Global Positioning System (GPS). The measured impedance bandwidths with VSWR less than 2 are 3.7% (1.19-1.235 GHz) and 1.2% (1.565-1.585 GHz), respectively, the measured 3 dB axial-ratio (AR) bandwidth are 0.9% (1.220-1.231 GHz) and 0.6% (1.572-1.581 GHz), respectively. A cavity is designed to render a unidirectional radiation pattern.

Compact Multi-Band H-Shaped Slot Antenna

Abstract: A compact triple-band H-shaped slot antenna fed by microstrip coupling is proposed. Four resonant modes are excited, including a monopole mode, a slot mode, and their higher-order modes, to cover GPS (1.575 GHz) and Wi-Fi (2.4-2.485 GHz and 5.15-5.85 GHz), respectively. Sensitivity study of the slot geometry upon the resonant modes have been conducted. The measured gains at these four resonant frequencies are 0.2 dBi, 3.5 dBi, 2.37 dBi, and 3.7 dBi, respectively, and the total efficiencies are -2.5 dB, -1.07 dB, -3.06 dB, and -2.7 dB, respectively. The size of this slot antenna is only 0.24λ0×0.034λ0, where λ0 is the free-space wavelength at 1.575 GHz, hence is suitable to install on notebook PC's and handheld devices.

Design of Wideband LNAs Using Parallel-to-Series Resonant Matching Network Between Common-Gate and Common-Source Stages

Abstract: A method is proposed to design wideband low-noise amplifiers (LNAs) made of cascaded common-gate (CG) and common-source (CS) stages with a parallel-to-series resonant interstage matching network. The first CG stage has a dual-band response, and the second CS stage has higher gain between these two bands. By applying the proposed interstage matching technique, conjugate matching is achieved at high and low bands, while the midband loss is compensated by the second stage. The output network of the first stage and the input network of the second stage resonate at the same frequency. Two wideband LNAs are designed based on this method and implemented in 0.18- μm RF-mixed signal CMOS process. The first LNA operates at 3.1-10.3 GHz, having 9.6-12.71 dB of power gain and 2.5-3.9 dB of noise figure (NF) at the power consumption of 13.4 mW. The second LNA operates at 14.3-29.3 GHz, having 8.25 ± 1.65 dB of power gain and 4.3-5.8 dB of NF at the power consumption of 13.9 mW.

Resonance in cylindrical-rectangular and wraparound microstrip structures

Abstract: A rigorous analysis of the resonance frequency problem of both the cylindrical-rectangular and the wraparound microstrip structure is presented. The problem is formulated in terms of a set of vector integral equations. Using Galerkin's method to solve the integral equations, the complex resonance frequencies are studied with sinusoidal basis functions which incorporate the edge singularity. The complex resonance frequencies are computed using a perturbation approach. Modes suitable for resonator or antenna applications are investigated. The edge singularity of the patch current is shown to have no significant effect on the accuracy of the results. It is shown that the HE/sub 10/ modes of the cylindrical-rectangular and wraparound patches are more appropriate for resonator applications. The HE/sub 01/ and TE/sub 01/ modes of the cylindrical-rectangular and wraparound patches, respectively, are efficient radiating modes. >

Metasurfaces: From microwaves to visible

Abstract: We review the basic physics and applications of a special class of planar metamaterials, often called metasurfaces, which are composed of optically thin and densely packed planar arrays of resonant or nearly resonant subwavelength elements. Electromagnetic properties and functionalities of such metasurfaces are defined by the structure and specific features of the subwavelength elements and their coupling type and strength, and they are often influenced by an underlying substrate. Metasurfaces may provide a full control of the reflected and transmitted fields, and they can be designed to possess many required properties replacing bulky optical components. Here, we describe different types of metasurfaces suggested in the past and recent years for a broad range of the operational wavelengths ranging from microwaves to the visible, and emphasize their important functionalities. We demonstrate that, despite a wide functional and structural diversity, all suggested metasurfaces can be associated with only several broad classes depending on intrinsic physical mechanisms of their polarizability. We suggest the functionality-based classification of metasurfaces, and clarify a link between their polarization response and field control capabilities. We also suggest a general approach to an optimal design of metasurfaces for many specific applications.

Multilayered media Green's functions in integral equation formulations

Abstract: A compact representation is given of the electric- and magnetic-type dyadic Green's functions for plane-stratified, multilayered, uniaxial media based on the transmission-line network analog along the aids normal to the stratification. Furthermore, mixed-potential integral equations are derived within the framework of this transmission-line formalism for arbitrarily shaped, conducting or penetrable objects embedded in the multilayered medium. The development emphasizes laterally unbounded environments, but an extension to the case of a medium enclosed by a rectangular shield is also included.

Radio frequency local area network

Abstract: An apparatus and a method for routing data in a radio data communication system having one or more host computers, one or more intermediate base stations, and one or more RF terminals organizes the intermediate base stations into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Communication between the host computer and the RF terminals is achieved by using the network of intermediate base stations to transmit the data.

Site-specific propagation prediction for wireless in-building personal communication system design

Abstract: The paper describes a geometrical optics based model to predict propagation within buildings for personal communication system (PCS) design. A ray tracing model for predicting propagation based on a building blueprint representation is presented for a transmitter and receiver located on the same floor inside a building. Measured and predicted propagation data are presented as power delay profiles that contain the amplitude and arrival time of individual multipath components. Measured and predicted power delay profiles are compared on a location-by-location basis to provide both a qualitative and a quantitative measure of the model accuracy. The concept of effective building material properties is developed, and the effective building material properties are derived for two dissimilar buildings based upon comparison of measured and predicted power delay profiles. Time delay comparison shows that the amplitudes of many significant multipath components are accurately predicted by this model. Path loss between a transmitter and receiver is predicted with a standard deviation of less than 5 dB over 45 locations in two different buildings. >

Dielectric Resonator Antennas: A Historical Review and the Current State of the Art

Abstract: This article presents a historical review of the research carried out on dielectric resonator antennas (DRAs) over the last three decades. Major research activities in each decade are highlighted. The current state of the art of dielectric-resonator-antenna technology is then reviewed. The achievable performance of dielectric resonator antennas designed for compactness, wide impedance bandwidth, low profiles, circular polarization, or high gain are illustrated. The latest developments in dielectric-resonator-antenna arrays and fabrication techniques are also examined.