Tze-Min Shen

Miniaturized Bandpass Filters With Double-Folded Substrate Integrated Waveguide Resonators in LTCC

This paper proposes miniaturized bandpass filters with double-folded substrate integrated waveguide (SIW) resonators using multilayer low-temperature co-fired ceramic (LTCC) technology. Formed by inserting a metal plate with two orthogonal slots into the cavity, the double-folded SIW resonator is used for the circuit size reduction with its footprint about a quarter of the conventional TE101 mode. With LTCC technology, there is more flexibility to organize the cavities of filters because of the 3-D arrangement. The vertically stacked cavities are coupled by ldquoLrdquo- or ldquoUrdquo-shaped slots, and if arranged horizontally, by an inductive window on the common sidewall or a suspended stripline between the cavities. Through experimental measurements and simulations at both the Ka- V -bands, it has been demonstrated that the proposed filter has compact sizes and good frequency responses. The area of the fully stacked Chebyshev filter has 88% size reduction in comparison with a three-pole planar waveguide filter, while the vertically stacked quasi-elliptic filter has 74% size reduction in comparison with a four-pole planar waveguide filter.

Design of Vertically Stacked Waveguide Filters in LTCC

This paper proposes four-pole quasi-elliptic function bandpass waveguide filters using multilayer low-temperature co-fired ceramic technology. The vertical metal walls of the waveguide resonators are realized by closely spaced metallic vias. Adjacent cavities are coupled by a narrow slot at the edge of the common broad wall or an inductive window on the sidewall. Two types of vertical coupling structures are utilized to achieve the cross coupling between nonadjacent resonators at different layers. With multilayer capability, there is more flexibility to arrange the cavities of coupled resonator filters in 3-D space. It is demonstrated by both the simulation and experiment that the proposed filter structures occupy a compact circuit area and have good selectivity. The filter with electric field cross coupling occupies a half area of a planar four-pole waveguide filter, while the filter with stacked vias cross coupling has 65% size reduction in comparison with a planar waveguide filter.

Design of Miniaturized Filtering Power Dividers for System-in-a-Package

Miniaturized power dividers with high-selectivity bandpass behavior are presented and analyzed theoretically in this paper. Based on the coupled-resonator topology, the circuit area of the proposed power divider can be reduced as the size of the assembled resonators shrinks. Therefore, in order to effectively reduce the circuit area and improve the stopband performance, the net-type resonator is selected to design the filtering power dividers. For demonstration, power dividers with Chebyshev- and quasi-elliptic bandpass responses have been designed and fabricated with microstrip in printed circuit boards. The highly symmetric structure of each power divider provides a low in-band magnitude and phase imbalances. Consequently, the proposed filtering power dividers have advantages of small size, sharp skirt selectivity, high isolation, and superior out-of-band performance. All measured results are in good agreement with the full-wave simulation results.

Design of Tri-Band Filters With Improved Band Allocation

A new design method for tri-band filters with improved band allocation is proposed. The design concept treats different band allocations with different methodologies. For the bands assigned to adjacent frequency regions, transmission zeros are introduced to split one of the single bands into two. For the bands that are assigned separately, different harmonic modes of stepped-impedance resonators are used to realize different passbands. Two design examples with different responses and band allocations are given, and were verified by experiments, as well as full-wave simulation results.

Design and Analysis of a 60-GHz CMOS Doppler Micro-Radar System-in-Package for Vital-Sign and Vibration Detection

This paper presents the first flip-chip-packaged and fully integrated Doppler micro-radar in 90-nm CMOS for noncontact vital-sign and vibration detection. The use of a smaller wavelength compared with previous works achieves the highly compact system for portable devices, and the radar design considerations at 60 GHz are discussed from both system and circuits points of view. The compact 60-GHz core (0.73

Dual-Band Vertically Stacked Laminated Waveguide Filter Design in LTCC Technology

\hbox{mm}^{2}

Design of Multimode Net-Type Resonators and Their Applications to Filters and Multiplexers

) provides a 36-dB peak down-conversion gain and transmits a radar signal around 0 dBm at 55 GHz. Quadrature generation at the intermediate frequency stage of the heterodyne receiver gives a power- and area-efficient solution to the null detection point issue, ensuring robust detection. By using single-patch antennas and without a high-power amplifier, the system demonstrates the first-pass success of human vital-sign detection at 0.3 m. The small mechanical vibration with a displacement of 0.2 mm can be detected up to 2 m away. At 60 GHz, target displacement comparable to wavelength results in strong nonlinear phase modulation and increases detection difficulties. A signal-recovery algorithm is proposed to improve the accuracy of vital-sign detection.

Design of Compact Quadruplexer Based on the Tri-Mode Net-Type Resonators

A new design method of dual-band filters with laminated waveguide (or substrate integrated waveguide) is proposed by taking advantage of the existence of multiple cavity modes. The major design concept is adequately choosing geometric shape of laminated waveguide resonators to control the frequency bands, and positions of open slots and feeding probes to realize the desired coupling coefficients and external quality factors at both bands simultaneously. Two design examples with third-order and quasi-elliptic filter responses are given and verified by experiments. By using the low-temperature co-fired ceramic technology, the laminated waveguide resonators are vertically stacked, and the filter size can be miniaturized.

A flip-chip-packaged and fully integrated 60 GHz CMOS micro-radar sensor for heartbeat and mechanical vibration detections

Net-type resonators with dual- and tri-mode electrical behaviors have been presented and analyzed theoretically in this paper. The proposed net-type resonator is constructed by a short-ended and several open-ended transmission-line sections, which has the advantages of small size and more flexible resonant frequency allocation and is therefore particularly suitable for applications to the design of microwave devices. To verify the usefulness of the proposed resonators, three experimental examples, including a dual-mode bandpass filter, a dual-passband filter, and a triplexer, have been designed and fabricated with microstrip technology. Each of the designed circuits occupies a very small size and has a good upper stop and performance. All measured results are in good agreement with the full-wave simulation results.

A Laminated Waveguide Magic-T With Bandpass Filter Response in Multilayer LTCC

A compact size and high isolation microstrip quadruplexer based on the tri-mode net-type resonators is proposed in this letter. The quadruplexer is composed of four folded tri-mode net-type resonator filters with one input and four output coupled-line structures. By adjusting the structural parameters of a single tri-mode net-type resonator, its first three resonant frequencies can be controlled and, thus, it can be utilized to implement a third-order bandpass filter when these resonant frequencies are suitably assigned. The proposed third-order bandpass quadruplexer is constructed by only four tri-mode resonators, showing a small circuit size. In addition, no additional five-pole matching junction is needed for the quadruplexer design. As a result, the proposed quadruplexer occupies an extremely small area, i.e., 0.27 λ0 by 0.09 λ0 (0.42 λg by 0.13 λg), while still keeping good isolation better than 40 dB for each channel.