Yo-Shen Lin

Wide-stopband microstrip bandpass filters using dissimilar quarter-wavelength stepped-impedance resonators

Wide-stopband and compact microstrip bandpass filters (BPFs) are proposed using various dissimilar quarter-wavelength (/spl lambda//4) stepped-impedance resonators (SIRs) for multiple spurious suppression. The use of /spl lambda//4 SIRs is essential in widening the filter stopband and reducing the circuit size. By properly arranging the individual /spl lambda//4 SIR, which has the same fundamental resonance frequency f/sub 0/, but has different spurious (harmonic) resonance frequencies, and also carefully misaligning the maximum current density nodes, several higher order spurious resonances may be suppressed so that a BPF with wide stopband may be realized. In this study, the basic concept of multiple spurious suppression is demonstrated by thoroughly investigating the spurious characteristics of the fourth-order interdigital BPFs, which consist of two different types of /spl lambda//4 SIRs. To widen the rejection bandwidth, the fourth-order coupled-resonator BPFs based on three and four different types of /spl lambda//4 SIRs are implemented and carefully examined. Specifically, a very wide-stopband microstrip BPF composed of four dissimilar /spl lambda//4 SIRs is realized and its stopband is extended even up to 11.4f/sub 0/ with a rejection level better than 27.5 dB.

Design of an LTCC tri-band transceiver module for GPRS mobile applications

This paper presents the results of a low-temperature co-fired ceramic (LTCC) module for tri-band GPRS mobile applications. The proposed transceiver module integrates the tri-band (EGSM/DCS/PCS) antenna switch, surface acoustic wave (SAW) filters for band selection, and a fully integrated tri-band transceiver IC into one LTCC package. Integrated passive devices include the diplexer, low-pass filters for harmonic rejection, transmission lines, and circuit elements for wiring/impedance matching. The module size is 13.8 mm/spl times/8.1 mm, with a packaged height of 1.8 mm. The module is compliant with the ETSI regulations and is currently working on commercially available mobile phones.

Wideband coplanar-waveguide bandpass filters with good stopband rejection

Wideband coplanar-waveguide (CPW) bandpass filters based on the cascade of CPW lowpass and highpass periodic structures are proposed. The upper and lower stopband characteristics of proposed bandpass filter can be easily designed by separately adjusting the lowpass and highpass sections, respectively. Specifically, two wideband CPW bandpass filters with sharp roll-off at passband edges and good stopband rejection are demonstrated.

Electromigration-induced UBM consumption and the resulting failure mechanisms in flip-chip solder joints

Eutectic PbSn flip chip solder joint was subjected to 5×103 A/cm2 current stressing at 150°C and 3.5 × 104 A/cm2 current stressing at 30°C. The under bump metallurgy (UBM) on the chip was sputtered Ni/Cu, and the substrate side was a thick Cu trace. It was shown through in-situ observation that the local temperature near the entrance of electrons from the Al interconnect to the solder became higher than the rest of the joint. The accelerated local Ni UBM consumption near the entrance was also observed. Once the Ni was consumed at a location, a porous structure formed, and the flow of the electrons was blocked there. It was found that the formation of the void and the formation of the porous structure were competing with each other. If the porous structure formed first, then the void would not be able to nucleate there. On the other hand, if the void could nucleate before the UBM above lost its conductivity, then the joint would fail by the void formation-and-propagation mechanism.

Highly selective microstrip bandpass filters for ultra-wideband (UWB) applications

Highly selective microstrip bandpass filters for UWB applications are proposed, by using the optimum distributed highpass filter structure of 11th-order to achieve a wide bandwidth from 3.1 to 10.6GHz as well as good selectivity. In addition, suitable filter layout is adopted to reduce the filter size and the number of vias required. Specifically, two compact 11th-order UWB microstrip bandpass filters with good selectivity are implemented and carefully examined.

Novel compact parallel-coupled microstrip bandpass filters with lumped-element K-inverters

Novel compact parallel-coupled microstrip bandpass filters are proposed by using additional lumped inductors to realize K-inverters between coupled-line sections to achieve an equivalent to the quarter-wavelength (/spl lambda//4) resonator filters. As a result, the filter order can be doubled without increasing the circuit area, and no repeated passband is observed at twice the center frequency. In addition, by introducing the cross-coupling effect, two transmission zeros at upper and lower stopbands may be created. Simple equivalent-circuit models are also established as effective design tools. Specifically, several compact fourth-order microstrip bandpass filters with good stopband rejection are implemented and carefully examined.

Novel inductance-incorporated microstrip coupled-line bandpass filters with two attenuation poles

A microstrip coupled-line bandpass filter with good stopband rejection is proposed. By introducing an additional shunt inductance to the conventional coupled-line filter, along with the capacitively coupled gap between coupled-line sections, two attenuation poles at upper and lower stopbands may be achieved without increasing the circuit area. The proposed filter exhibits good stopband rejection with no repeated passband at twice the center frequency as compared to the conventional coupled-line filters. Specifically, a microstrip coupled-line bandpass filter centered at 2.4 GHz with 5.4% 3-dB bandwidth and two attenuation poles is implemented.

Extended-stopband bandpass filter using both half- and quarter-wavelength resonators

A novel quasielliptic microstrip bandpass filter (BPF) using both half- and quarter-wavelength resonators is proposed. With the quarter-wavelength (lambda/4) resonators placed in the interstage, the filter spurious passband can be pushed up to 3 f0 where f0 stands for the passband center frequency. To improve the stopband characteristics, a modified stopband-extended filter is implemented, utilizing the multiple transmission zeros placed at specified frequencies to achieve good frequency selectivity and out-of-band rejection. The modified filter provides a 22.5-dB rejection level from 1.14 f0 to 5.2 f0

A compact LTCC branch-line coupler UsingModified-T equivalent-circuit modelfor transmission line

In this letter, a compact branch-line coupler is proposed by making good use of the three-dimensional layout capability of the low-temperature co-fired ceramic (LTCC) substrate. This branch-line coupler is accomplished by using lumped-inductors and lumped-capacitors to realize the modified-T equivalent-circuit model for the transmission line so that the circuit size may drastically be reduced. Specifically, a very compact LTCC branch-line coupler with a size of 0.079/spl lambda//spl times/0.0717/spl lambda/ is implemented and carefully examined, where /spl lambda/ is the wavelength of the multilayer structure at the operating frequency f/sub 0/.

Analysis and Design of New Single-to-Balanced Multicoupled Line Bandpass Filters Using Low-Temperature Co-Fired Ceramic Technology

This paper presents the design procedure and performance of a new single-to-balanced multicoupled line bandpass filter structure. The proposed filter is composed of a multicoupled line of electric length much shorter than lambda/8 along with shunt capacitors loaded at suitable positions. By a proper design of ground terminations for the multicoupled line, the proposed filter is simultaneously equipped with the functionality of a bandpass filter, a balun, and an impedance transformer. The bandpass characteristic can be easily developed to higher order for better selectivity. The graph-transformation method for coupled-line analysis is adopted to make the design procedure efficient and intuitive. To validate the design procedure and feasibility of proposed filter for mobile applications, two design examples with different filter order, impedance transformation ratio, fractional bandwidth and center frequency have been implemented in chip type by using the low temperature co-fired ceramic technology. The second-order design is realized in a chip size of 2012, while the third-order one is realized in a chip size of 2612. Moreover, an additional transmission zero in the upper stopband can be achieved and controlled flexibly by adjusting the outer printed circuit board layout with minimum effect on passband performance. Fabrication and measurement of these designs show that compact sizes and good agreements between measured and simulated results can be obtained, which demonstrate their suitability in modern mobile communication applications.