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In Part I of this two-part work, we have presented the theoretical foundation and physical mechanism of the mode-selective transmission line (MSTL). This part is devoted to its excitation scheme, practical transition design, and experimental verification. The MSTL excitation is first explained by comparison with a conductor-backed coplanar waveguide (CBCPW). To produce the specific mode excitation, an ultrabroadband transition between CBCPW and MSTL is proposed. It has a tapered structure operating as a tapered-mode coupler, which supports smooth evolution from the fixed CPW mode of CBCPW to the frequency-dependent dominant mode of MSTL. This modal evolution along the transition is analytically treated based on a local normal mode theory. Couplings between the local normal modes are negligible as a result of gradual tapering, thereby effectively suppressing higher order modes in MSTL and sustaining a mode purity over an ultrabroad frequency range. For experimental demonstration purposes, back-to-back CBCPW-to-MSTL transition circuits are physically realized. The measured results are in agreement with the prediction, showing a return loss of 15 dB from 3 to 109 GHz; the single transition introduces a relatively low insertion loss of 1.84 dB at 100 GHz. The propagation characteristics of MSTL are also extracted from the measured S-parameters, which provides an excellent validation of the proposed structure. [ABSTRACT FROM AUTHOR]

This paper presents design, fabrication, and high-frequency characterization of through-silicon-vias (TSVs) with benzocyclobutene (BCB) as the dielectric liner to exploit its low dielectric constant. Fabrication processes for BCB polymer liner TSVs are developed, and BCB-liner TSVs have been successfully fabricated in both low-resistivity silicon and high-resistivity silicon substrates for comparison. A de-embedding method that enables extraction of S-parameters from cascade TSV chains is developed based on the thru-reflect-line calibration algorithm, and the S-parameters of BCB-liner TSVs have been obtained from the measured transmission properties of cascade TSV chains with frequencies up to 25 GHz. Measurement results show that the BCB liner improves transmission properties of TSVs up to 10 GHz compared with SiO2-liner TSVs, and sub-strate resistivity dominates transmission properties for frequencies higher than 10 GHz. [ABSTRACT FROM AUTHOR]

Due to the advantages of ease of fabrication, low cost, and potential high reliability, through-silicon-vias (TSVs) using low-resistivity silicon posts as conductors and circular polymer liners as insulators have been developed for 3-D integration of microelectromechanical systems and microsensors. However, the large coefficients of thermal expansion (CTEs) of polymers lead to significant thermal stresses, which may cause silicon cracks. This paper reports the fabrication, thermal stress simulation, and thermal tests of a silicon TSV using benzocyclobutene (BCB) as the insulator. Silicon TSVs with high-aspect-ratio BCB liners have been fabricated by developing a vacuum-assisted filling method to achieve void-free BCB insulators. Finite-element method (FEM) is employed to simulate the thermal stresses caused by the mismatch in the CTE between silicon and BCB. High-temperature curing experiments show that crack in silicon substrates and silicon posts occurs on TSVs with specific dimensions. By correlating the results of FEM simulations and crack tests, the critical stress that causes silicon cracks is revealed, and design guidelines are proposed to achieve crack-free silicon TSVs. [ABSTRACT FROM PUBLISHER]

The use of air gaps instead of SiO2 as insulators for through-silicon vias (TSVs) has been demonstrated to reduce the thermal stresses and the TSV capacitance of a 3-D integrated system. However, since the Cu plug in air-gap TSVs lacks support and fixation at the sidewalls, the mechanical strength is a serious concern. This paper for the first time reports the mechanical and humidity reliabilities of air-gap TSVs. Reliability tests including free drop test, vibration test, and accelerated moisture test are performed, and the failure mechanisms are analyzed. The residual stresses in silicon substrates are also measured using micro-Raman Spectroscopy. Experimental results show that the premetal dielectric that acts as the only support for Cu plugs is the weak point causing mechanical reliability issues, and oxidation of Cu plugs at high moisture and high temperature is the main reason for humidity reliability problems. Multilayer bonding of TSV chips to constitute a 3-D system remarkably increases the mechanical and humidity reliabilities of air-gap TSVs because of the support and protection provided by the bonding chips. [ABSTRACT FROM AUTHOR]

A novel surface-mounted monoblock high Q dielectric filter is presented in this paper. The proposed filter is constructed on the basis of a surface-metalized dielectric monoblock and is surface mountable on a printed circuit board (PCB) by means of a reflow process. The monoblock dielectric filter can be easily manufactured by mold casting. Metal caps on the surface and through holes in dielectric body are introduced for tuning capability. The input/output coupling is realized by inserting a stepped probe into the dielectric cavity through a via structure on the PCB. A novel electric coupling method using microstrip line is presented for easy control of coupling coefficient by adjusting the length and width of the microstrip line and flexible routing of cross couplings. One prototype 8-2 surface-mounted monoblock dielectric filter operating at 1.9 GHz with 84 MHz bandwidth is designed, fabricated, and measured. The measured insertion loss at center frequency is 0.73 dB with 0.6 dB ripple and corresponding unloaded Q factor of around 1700, demonstrating that the proposed filter architecture is applicable to a radio front-end of advanced wireless communication systems. [ABSTRACT FROM AUTHOR]

In this paper, the development of an innovative micro-coaxial line technology is presented and developed for dc-to-millimeter-wave broadband applications. This nondispersive line is fabricated using a simple photoimageable thick-film process. Wave-guiding properties of the developed micro-coaxial line are extracted from 1 to 110 GHz, showing an extremely broadband operation. A single transition from micro-coaxial line to grounded coplanar waveguide is used to cover the entire frequency range available through single vector network analyzer. Passive devices are then demonstrated in the form of a 60 GHz band-pass filter and an 8 dB coupler using vertically coupled lines. Measured results of the demonstrative filter show an excellent agreement with simulated results, which present very good performances with 1.5 dB insertion loss over the frequency band of interest. The broadband coupler exhibits an exceptional multioctave bandwidth (from 20 to 82 GHz) and low loss at 1.5 dB. [ABSTRACT FROM PUBLISHER]

Substrate integrated waveguide (SIW) technology provides an effective solution for the low-cost and high-performance interconnect and packaging of microwave and millimeter wave systems. In this paper, Ka-band four-degree bandpass filters having asymmetric frequency response, which are required in the design of transmit and receive diplexers for high rejection between neighboring channels, are proposed and realized on an SIW platform. The filters are self-packaged due to the fact that a conductor-backed coplanar waveguide is used to directly excite the filters. Higher-order resonant mode is used to achieve the required negative coupling on the basis of a single-layer SIW. The proposed filters, having the same center frequency of 35 GHz and pass bandwidth of 1.3 GHz, are fabricated on a conventional Rogers RT/Duroid 6002 substrate with thickness of 0.508 mm by using a low-cost printed circuit board process. Measured results of those filters, which exhibit high single-sided selectivity and minimum in-band insertion loss of about 1.25 dB, agree well with simulated results. [ABSTRACT FROM PUBLISHER]

In this paper, a novel input/output (I/O) coupling multiplier circuit for conveniently increasing I/O coupling of a wideband coupled-resonator filter/diplexer is proposed. The multiplier circuit consists of a shunt capacitor and a negative phase shift. By appropriately shunt connecting a capacitor in the vicinity of an I/O port, the I/O coupling can be effectively increased. Compared to conventional approaches of increasing I/O coupling for a wideband application, using the multiplier circuit allows much less perturbing the resonant frequency of the first resonator. For many resonator configurations such as helical resonator, to which the tapping probe could not be adjusted continuously, the multiplier circuit provides a convenient way to control I/O coupling. In this paper, the working mechanism of the proposed circuit is well proved theoretically. The usefulness of the multiplier circuit has been demonstrated for coaxial combline cavity resonators and helical resonators, both for filter and diplexer applications. As a practical example, the multiplier circuit is applied to a wideband UHF helical resonator diplexer. [ABSTRACT FROM PUBLISHER]

This paper proposes and presents a class of substrate integrated waveguide (SIW) power dividers/combiners based on a modified Wilkinson architecture. The proposed design consists of a ring-type circuit of \(1.5~\lambda _{g}\) length with three waveguide ports. Impedance variation without affecting cutoff frequency and integration of isolation resistance are the two major limitations in connection with the design of SIW Wilkinson structures. Central ring part with different thickness ensures different impedance in the first proposed scheme while the half-mode SIW in the second option. As for the second limitation, the optimal configuration of integrating the isolation resistance is studied. A version without resistance is also examined using a broad-wall series slot. To validate the proposed concept, a bilayered circuit with standard Printed circuit board prototype was fabricated and measured. A table summarizing performances of all the proposed circuits shows a bandwidth of around 25% at the 10 dB reference. A negligible additional insertion loss is observed. The proposed design techniques are found useful at millimeter-wave frequencies where reduced physical dimensions make a circuit configuration suitable for low-cost implementation. This concept is also valid for rectangular waveguide counterparts. [ABSTRACT FROM AUTHOR]

This paper presents and demonstrates a class of 3-D integration platforms of substrate-integrated waveguide (SIW). The proposed right angle E-plane corner based on SIW technology enables the implementation of various 3-D architectures of planar circuits with the printed circuit board and other similar processes. This design scheme brings up attractive advantages in terms of cost, flexibility, and integration. Two circuit prototypes with both 0- and 45^\circ vertical rotated arms are demonstrated. The straight version of the prototypes shows 0.5 dB of insertion loss from 30 to 40 GHz, while the rotated version gives 0.7 dB over the same frequency range. With this H-to-E-plane interconnect, a T-junction is studied and designed. Simulated results show 20-dB return loss over 19.25% of bandwidth. Measured results suggest an excellent performance within the experimental frequency range of 32–37.4 GHz, with 10-dB return loss and less than \pm4^\circ phase imbalance. An optimized wideband magic-T structure is demonstrated and fabricated. Both simulated and measured results show a very promising performance with very good isolation and power equality. With two 45^\circ vertical rotated arm bends, two antennas are used to build up a dual polarization system. An isolation of 20 dB is shown over 32–40 GHz and the radiation patterns of the antenna are also given. [ABSTRACT FROM PUBLISHER]

The recently developed mode-selective transmission line (MSTL) is proposed and exploited as an alternative approach to accommodate the growing and future ultrafast interconnects requirements of ultralarge-scale integration for high density, speed, performance, and bandwidth (BW). A parametric study is performed to optimize the MSTL structure for high-speed global interconnects and to provide high-performance signal integrity. Picosecond and rectangular pulse propagations on MSTL are examined, and pulse distortion, broadening, ringing, and reflection are characterized. An eye diagram is also shown to examine the jitter and noise. Due to our limited low-cost printed circuit board (PCB) fabrication accuracy, the frequency-domain measurement is carried out up to 110 GHz. Our optimal fabricated MSTL structures show an ultrawide absolute BW covering dc, maintain more than 200% relative BW while transmitting around 90° bends, and achieve a measured crosstalk of better than −45 dB over the entire band. Time-domain characterizations imply that the PCB-based MSTL accommodates data rates greater than 200 Gb/s. This technology allows, for the first time, the transmission of ultrahigh-speed electrical signal and picosecond pulse transmission through global interconnects with much lower dispersion and loss than today’s technologies. [ABSTRACT FROM AUTHOR]

This paper proposes a robust option for developing a new class of efficient and cheap antenna array based on patch array fed by substrate-integrated waveguide (SIW) through slot apertures for wireless backhauling applications. It consists in performing the feed network in SIW and the radiating structure in microstrip technology. The microstrip lines are coupled to the slots on the top wall of the SIW. Hence, it is demonstrated that the best alternative of the costly, heavy, and bulky rectangular waveguide feeder is SIW, which provides miniaturization, cost reductions, performance enhancements, and easy integration with patch array antennas. The experimental prototype presented in this paper demonstrates the efficiency of the design method and the feasibility of creating low-cost moderate-bandwidth millimeter-wave planar $8\times 8$ patch antenna array configurations in two stacked substrates to get ultracompact antenna module. The principle of achieving such high-quality antenna array is presented in detail along with experimental verification of theoretical results to validate the design procedure and demonstration of the feasibility of implementing the array by means of relatively inexpensive compact structures. The maximum gain is around 23 dBi at 22.4 GHz, the measured impedance bandwidth is 5%, and the efficiency is around 70%. [ABSTRACT FROM PUBLISHER]

We investigate the application of perfect magnetic conductor (PMC) packaging for a nonsmooth perfect electric conductor surface, caused by metalized via holes. The PMC shielding is artificially built by a metal lid of pins, based on the gap waveguide (GW) technology. As a foundation, the effects of via hole in a unit cell are studied first considering its diameter, substrate thickness, pin size, pin height, as well as relative position between the via hole and the pin. The via adjacent space and pin rows are also considered for a general grounded coplanar waveguide along with ground vias. The effectiveness of package for such a transmission line containing metalized via holes is then verified experimentally. It is shown that the measured performance agrees well with the simulation. This paper presents a guideline for the GW-based PMC packaging technology. [ABSTRACT FROM AUTHOR]

For emerging millimeter-wave wireless applications at W- and E-bands, active components including LNA and power amplifier are preferably fabricated or surface-mounted on the materials of a high dielectric constant (such as CMOS and MHMIC). On the other hand, antennas or radiating elements should be developed on relatively low-dielectric constant substrates for the enhancement of gain and bandwidth. Therefore, the development of a wideband transition from high-to-low dielectric constant substrates becomes necessary because the use of wire bonding schemes brings up packaging, interconnects, and manufacturing problems at millimeter-wave frequencies. This paper presents a novel integrated wideband transition of substrate integrated waveguide (SIW) on high-to-low dielectric constant substrates. The transition is made of a single-layer structure, which consists of a tapered high-dielectric constant substrate that connects two SIWs. Because of the waveguide-based structure of the transition, it has a self-shielded configuration, and its interference is minimum. Simulated and measured results show that the bandwidth of the proposed transition covers almost the entire W- and E-bands with low insertion loss. [ABSTRACT FROM AUTHOR]