Chien-Hsiang Huang

Dual Wideband Printed Monopole Antenna for WLAN/WiMAX Applications

A novel printed monopole antenna with dual widebands is presented for simultaneously satisfying wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The antenna structure consists of a rectangular monopole with a microstrip feedline for excitation and a trapezoid conductor-backed plane for band broadening. The measured 10 dB bandwidth for return loss is from 2.01 to 4.27 GHz and 5.06 to 6.79 GHz, covering all the 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands

High-performance frequency-hopping transmitters using two-point delta-sigma modulation

This paper presents a 2.4-GHz high-performance frequency-hopping (FH) transmitter using two-point delta-sigma modulation (TPDSM). Two bottleneck problems in the implementation have been studied rigorously. One is the nonlinear performance of a phase-locked loop (PLL). The other is the inherent gain and delay mismatches between two modulation points. Both nonlinear and mismatch factors dominate the modulation accuracy in the closed PLL. Our formulation can predict the dependencies of modulation accuracy on both factors quite successfully. Comparison of the averaged frequency deviation and frequency-shift-keying (FSK) error between theory and measurement shows excellent agreement. The implemented TPDSM-based FH Gaussian FSK transmitter can achieve 2.5-Mb/s data rate along with 15-/spl mu/s PLL stable time with only 2.2% FSK error under good design and operating conditions.

Highly Miniaturized Multiband Bandpass Filter Design Based on a Stacked Spiral Resonator Structure

This paper describes a stacked spiral resonator (SSR) structure for designing very compact multiband bandpass filters. The resonant frequencies of the proposed SSR structure can be determined by designing the spiral geometry and controlling the mutual coupling in a stacked structure. The multiple passband bandwidths can then be determined by the spacing of different layer patterns between two coupled SSRs. An adequately designed geometry of the input/output resonator with a tapped-line feed can achieve matching conditions for all passbands simultaneously. Moreover, multiple transmission zeros created on both sides of each passband provide high stopband roll-off rates.

Integrated Transformer-Coupled Balun Bandpass Filters With an Optimal Common-Mode Rejection Ratio

This paper describes a compact transformer-coupled balun bandpass filter design based on integrated circuit technology. Using a planar transformer with high-density fully symmetrical wiring not only greatly reduces the component size, but also provides a superior balance at the differential output ports. In addition, applying the tapped feed-line structure to the balun bandpass filter is accomplished by carefully studying the impedance-matching method and transmission-zero mechanism. Interestingly, the proposed balun bandpass filter can guarantee an optimal common-mode rejection ratio level in a specific operating frequency range by precisely controlling the fractional bandwidth of the filter passband.

Optimum Design of Transformer-Type Marchand Balun Using Scalable Integrated Passive Device Technology

A simple and effective technique for designing transformer-type Marchand baluns is presented in this paper. The coupled-line sections required in a Marchand balun design are realized using planar transformers with a scalable model. The proposed design technique enables the prediction and optimization of Marchand balun performance over a wide range of layout and process parameters. To demonstrate the optimization process, Marchand baluns are designed for implementation using silicon and glass integrated passive device (IPD) technologies. Finally, experimental verification shows very good agreement between the modeled and measured results, thereby validating the IPD design optimization.

Very Compact Stacked LC Resonator-Based Bandpass Filters With a Novel Approach to Tune the Transmission Zeros

This letter presents very compact stacked LC resonator structures and their coupling and excitation techniques for designing the bandpass filters operating in the 3.5 GHz WiMAX band. Using a coupled stacked LC-resonator structure not only greatly reduces the overall size but also can create multiple transmission zeros to enhance roll-off rate or desired stopband rejection for the designed bandpass filters. Furthermore, this letter develops a simple technique of etching a rectangular C-shaped slot in the bottom ground plane to flexibly adjust the transmission-zero frequencies without changing the size and shape of the filter.

Very compact transformer-coupled balun-integrated bandpass filter using integrated passive device technology on glass substrate

This paper presents a transformer-coupled resonator structure to integrate a balun into a bandpass filter using integrated passive device technology on glass substrate. The use of the transformer not only greatly reduces the size of the bandpass filter, but also easily provides the coupling to the balanced output ports. In addition, the tapped feed-lines are used to obtain a good impedance match at all ports, and create extra transmission zeros to enhance the desired stopband rejection. The presented balun-integrated bandpass filter has an overall smaller area and lower insertion loss than the separate designs, showing a great potential to be embedded in a glass carrier for wireless 3D packaging and integration.

Design and modeling of planar transformer-based silicon integrated passive devices for wireless applications

This paper presents design and modeling techniques for integrated passive devices (IPDs) that can be stacked with RF chips in a highly integrated three-dimensional IC for wireless applications. The research starts to study winding and modeling techniques for high-efficiency planar transformers. In an Above-IC process for silicon IPDs, the planar transformers realized can provide a passive efficiency as high as near 90%. Based upon the proposed and modeled high-efficiency planar transformers, the research explores novel planar transformer-based structures for various kinds of wireless passive components including baluns, bandpass filters and power combiners to achieve miniature size as well as high performance.

Design and Implementation of Embedded Miniature Bandpass Filters for RF-System-in-Organic-Package Applications

A simple bandpass filter architecture composed of three spiral inductors and two parallel-plate capacitors is presented to be suitable for being embedded in a low-cost organic laminate substrate for RF system-in-package applications. Although only five components are used, the presented organic bandpass filter designs can feature themselves with a third-order Chebyshev response plus multiple transmission zeros, resulting in a low and flat insertion loss in the passband as well as a high attenuation rate in the roll-off region. Due to the use of so few components, the organic bandpass filters implemented in the proposed architecture can be size-competitive with the low-temperature cofired ceramic (LTCC) bandpass filters.

A comparison of two alternative architectures of digital ratioed compressor design for inner product processing

Inner product calculations are often required in digital neural computing. The critical path of the inner product of two binary vectors is the carry propagation delay generated from individual product terms. In this work, two novel architectures to arrange digital ratioed compressors are proposed to reduce the carry propagation delay in the critical path. Besides, the carry propagation delay estimation of these compressor building blocks is derived and compared. The theoretical analysis and Verilog simulation both indicate that one of the compressor building blocks we present here might offer a sub-optimal solution for the basic building blocks used in digital hardware realization of the inner product computation.