Yves Cassivi

Dispersion characteristics of substrate integrated rectangular waveguide

Dispersion properties of the substrate integrated rectangular waveguide (SIRW) are rigorously obtained using the BI-RME method combined with the Floquets theorem. Our analysis shows that the SIRW basically has the same guided-wave characteristics as the conventional rectangular waveguide. Empirical equations are derived from the calculated dispersion curves in order to estimate the cutoff frequency of the first two dominant modes of the SIRW To validate the analysis results, an SIRW guide was designed and measured. Very good agreements between the experimental and theoretical results were obtained.

The substrate integrated circuits - a new concept for high-frequency electronics and optoelectronics

A new generation of high-frequency integrated circuits is presented, which is called substrate integrated circuits (SICs). Current state-of-the-art of circuit design and implementation platforms based on this new concept are reviewed and discussed in detail. Different possibilities and numerous advantages of the SICs are shown for microwave, millimeter-wave and optoelectronics applications. Practical examples are illustrated with theoretical and experimental results for substrate integrated waveguide (SIW), substrate integrated slab waveguide (SISW) and substrate integrated nonradiating dielectric (SINRD) guide circuits. Future research and development trends are also discussed with reference to low-cost innovative design of millimeter-wave and optoelectronic integrated circuits.

Low cost microwave oscillator using substrate integrated waveguide cavity

A topology is proposed for designing a low-cost microwave oscillator. This new feedback oscillator makes use of a substrate integrated waveguide (SIW) cavity that acts as a frequency selector as well as a feedback-coupling device. The oscillator is stabilized by using an injection-locking scheme. A 12.02-GHz oscillator prototype was designed. Experimental results for phase noise, locking range, and quality factor of the new circuit are presented. An external Q of 178 was measured.

Substrate integrated nonradiative dielectric waveguide

A new substrate integrated circuits (SICs) fabrication technique is proposed for realizing nonradiative dielectric (NRD) waveguide circuits. This new technique called substrate integrated NRD (SINRD) guide allows the NRD guide be integrated within a dielectric substrate by drilling a pattern of air holes. Dispersion analysis and design considerations of the new structure are discussed. A hybrid integrated scheme of planar and SINRD circuits is demonstrated for the first time with simulation and measurement results.

Substrate integrated NRD (SINRD) guide in high dielectric constant substrate for millimetre wave circuits and systems

The use of high dielectric constant substrate such as alumina is proposed and investigated for the realization of substrate integrated non-radiating dielectric (SINRD) guide. This work demonstrates that electromagnetic bandgap (EBG) phenomena are very much pronounced in this case, which fundamentally limits the design of air hole patterns. A prototype of 94GHz alumina SINRD guide circuit with back-to-back WR10 transitions is designed and realized for the first time. Measured results of this circuit on this basis of the proposed technology are presented and discussed.

Design considerations of engraved NRD guide for millimeter-wave integrated circuits

Practical construction of nonradiative dielectric (NRD) guide components such as filters, junctions, or hybrid planar NRD-guide circuits is rather difficult because of the tedious alignment and tolerance requirement of various separate NRD-guide elements. To overcome this hurdle, we present a new scheme called the engraved NRD guide (ENRD). This ENRD guide is an NRD guide whose outline is machined out of a single dielectric block, thereby eliminating the alignment constraint, and allowing a better precision for physical design, realization, and integrity of the overall circuit. Design considerations and procedures of the ENRD guide are studied and discussed in this paper, which suggest the predominance of gap dimension in obtaining a quasi-nonradiative condition with similar propagation properties as a normal NRD guide. It also shows that the amount of dielectric material left in support of the whole structure alignment could greatly affect the leakage level of the guide. An ENRD-guide 90/spl deg/ bend and filter were designed and measured. Investigation of the ENRD-guide filter leads to the characterization of an evanescent LSM/sub 10/ mode in the air gap region between the resonators necessary for reducing its insertion loss.

Analysis and design of bridged NRD-guide coupler for millimeter-wave applications

A new nonradiative-dielectric (NRD)-guide directional coupler using two NRD waveguides interconnected with a bridge is proposed and demonstrated. Propagation constants of the bridged NRD-guide couplers are investigated with an electric-field integral-equation method, and modeling results show that there is a maximum of coupling coefficient when the thickness of the bridge is made around 0.68 of the plate separation. In this case, the coupling length is reduced approximately 60% and the bandwidth under the tolerance limits of /spl plusmn/0.5 dB of deviation for 3-dB coupling is nearly doubled with reference to its conventional counterparts. The use of a bridge not only improves the mechanical stability, but also makes the coupler performance reproducible. Experimental prototypes are fabricated with two 90/spl deg/ elbow bends that are used for the arms and the bridge-connected coupler section is terminated at both ends by tapered half-circle sections. A calibration procedure is used to remove mismatch effects between the NRD-guide and the rectangular waveguide in the measured results. Advantages of the new coupler as a passive component are shown for millimeter-wave integrated circuits.

Hybrid planar NRD-guide magic-tee junction

A new magic-tee circuit is proposed and developed, which is based on the hybrid integration technology of a planar and nonradiative dielectric (NRD) guide. The magic-tee junction combines an NRD-guide T-junction with a microstrip T-junction. Furthermore, LSM/sub 10/-mode radiators are introduced in the magic-tee circuit to reduce its resonance problem. Measured results show that an isolation of 20 dB can easily be achieved between the sum and difference ports.

Low-cost RF and microwave source design using substrate integrated waveguide technique

This work presents a novel approach to designing low-cost RF and microwave power source using substrate integrated waveguide (SIW) components. The proposed example involves two oscillators and a power combiner. The oscillators are designed and constructed on the basis of an SIW resonant cavity to obtain a high Q factor. An inter-injection-locked topology is used to interconnect the oscillators and provide an in-phase that can improve the overall performance. The power combiner is constructed with the SIW scheme, thus allowing the system to reduce loss inherent to the transition between components, and also decrease the manufacturing cost. Design considerations and experimental results are presented.

Recent advances of hybrid planar/NRD-guide technology for millimeter-wave integrated circuit design

In this paper, we look at different possibilities and advantages of our early proposed hybrid planar and nonradiative dielectric (NRD) guide technology in the design of various millimeter-wave circuits. First of all, an overview of the NRD guide technology progress is presented. It indicates that the hybrid planar/NRD-guide (HP/NRDG) technology provides a straightforward assembly of MMIC circuits with NRD-guide. To begin with, a simple fabrication technique for NRD-guide is described, which allows the fabrication of complex NRD circuits in a single step. Then, a new magic tee junction based on HP/NRDG technology is presented with measured results. New mode suppressor topologies compatible with the HP/NRDG technology are discussed for spurious waveguide modes, the LSE/sub 10/ mode and also the LSM/sub 10/ mode. Finally a discussion is made on different design possibilities of HP/NRDG power amplifier topologies. The present overview of some of our ongoing research work on the HP/NRDG technology suggests that the realization of a low-cost millimeter-wave transceiver is possible.