Gaëtan Prigent

Design of narrow-band DBR planar filters in Si-BCB technology for millimeter-wave applications

This paper discusses a method used to design planar bandpass filters for millimeter-wave applications in U- and W-band frequency ranges. For technical reasons, these filters have to be implemented on silicon-based technology. So as to decrease the insertion losses levels inherent in silicon substrate, we propose a thin-film microstrip-like technology implemented on a benzocyclobutene layer. In addition, a dual-behavior resonator-based filter topology enabled us to fit a hardened specification. In association with this new topology, we employed an automated design procedure that combines both circuit and full-wave simulations. It is based on a statistical sensitivity study performed by design-of-experiment analysis.

Fabrication and characterization of low-loss TFMS on silicon substrate up to 220 GHz

This paper presents the results of the fabrication and characterization up to 220 GHz, of thin-film microstrip (TFMS) transmission-line structures. The transmission lines are fabricated on a low-resistivity silicon substrate (/spl rho/=10 /spl Omega/ /spl middot/ cm). TFMS lines with a thick dielectric layer (20 /spl mu/m of benzocyclobutene is used here) present losses of 0.3 dB/mm at 94 GHz and 0.6 dB/mm at 220 GHz. Thus, using this technology, it will be possible to develop monolithic microwave integrated circuits on a silicon substrate.

Wide- and narrow-band bandpass coplanar filters in the W-frequency band

This paper deals with the design of passive coplanar devices in the W-frequency band. As long as coplanar transmission lines are correctly dimensioned, analytical models based on quasi-TEM approximation can be used. Such models are associated with a correct definition of the reference planes at the junctions and employed for junction discontinuities, T- and cross-junctions. In order to validate these assertions, simulated and experimental data on classical quarter-wavelength shunt-stub filters are first presented. Then the design of traditional coupled-line filters is examined. The problems in terms of insertion loss associated with these kinds of narrow-band applications are discussed here. Minimization of insertion losses requires increasing the width of the strips. Consequently, the design becomes complex and modeling using transmission-line models less accurate. Nevertheless, as an optimization procedure is needed to tune the filter theoretically, such a very fast design method is necessary. Simulated and experimental results in the range 500 MHz to 110 GHz are compared throughout the paper.

Achievable bandwidth of a quarter wavelength side-coupled ring resonator

Studies on the achievable range of bandwidth of a side-coupled ring resonator bandpass filter are presented. The elements of the resonator susceptible on varying the filter bandwidth are identified and design solutions are given in order to push the bandwidth to its minimum and maximum values. Based on the side-coupled ring resonator topology, two microstrip filters were designed at 10 GHz to achieve the narrowest and widest bandwidth with respect to insertion losses and technological limitation. Results of the studies with the given technology show that the ring resonator is suitable to address bandwidth from narrow (3.6%) to wide (31%). These concepts are validated through simulations and experiments for filters implemented on alumina substrate.

Improvement of an inverted microstrip line-based microwave tunable phase-shifter using liquid crystal

This paper deals with the study of electrically tunable phase-shifters based on the use of liquid crystals. First, the dielectric characterization of the commercial liquid crystal involved in our investigations allowed us to determine its dielectric anisotropy. Secondly, two phase-shifter configurations were studied. Both structures propose inverted microstrip line with coplanar accesses, but they are based on a different design of the transmission line. The measurements carried out with the first one evidenced an efficient phase shift. The second one showed considerable improvement in performances.

Widely tunable high-Q SIW filter using plasma material

This paper presents a novel concept to tune the resonant frequency of an evanescent-mode substrate integrated waveguide resonator while maintaining a high-Q in the tuned frequency range. The tunability is based on the insertion of vertical switchable capacitive post within SIW cavity. The filter is tuned from 18GHz to 7.5GHz, with insertion losses ranging from 0.8 to 2 dB in the frequency range for 1.4% bandwidth filter. The main interest of this work is the use of the argon material under high pressure and DC voltage to generate a dense plasma media.

Quarter wavelength side-coupled ring filters for V-band applications

Designs of three bandpass filters based on quarter wavelength side-coupled ring resonator are presented for V-band applications. Centered at around 60 GHz with three different bandwidths of 2.4%, 6.2% and 11.27%, the filters are designed on a 25-mum-thick benzocyclobutene (BCB) substrate deposited on a 400-mum-thick silicon bulk. In the filter designs, three technology configurations involving multilayer microstrip and coplanar waveguide (CPW) environment are considered to achieve flexibility in coupling. Results from electromagnetic simulations of the filters are presented through this paper.

Series-cascaded ring resonators for compact microwave filter with high rejection

Very selective fifth order bandpass ring filter is presented based on two series-connected quarter-wavelength side-coupled ring resonators. As the connection between the two quarter-wavelength lines forms a half-wavelength resonator, an extra pole is produced, leading to a total of five poles since each ring resonator presents two poles. This adds to the compactness of the overall filter and improves the selectivity and rejection. Centered at 2 GHz, the filter layout is simulated and implemented on FR4 substrate using microstrips. Filter simulation and measurement results are presented to validate the idea.

Design of narrow band-pass planar filters for millimeter-wave applications up to 220 GHz

This paper deals with the design of passive band-pass filters in thin film microstrip (TFMS) technology for millimeter-wave application in G-band frequency range. The filters to be designed are realized on a BCB-based technology. Quality of the design method as well as technological process has already been fully tested in W-band at 94-GHz. Thus, transposition to higher frequency is investigated at 180 GHz. In such a frequency range, designers are faced to technological point locks. So as to overcome them, specific design techniques are discussed for several filter realization.

Band-pass coplanar filters in the G-frequency band

This letter is devoted to the design of passive coplanar devices in the G-frequency band from a classical electrical circuit approach. Indeed, as long as coplanar transmission lines are correctly dimensioned, analytical models based on quasi-TEM approximation can be used. Simulated and experimental results in the range 0.5 to 220GHz are compared. They are exemplified with a 200-GHz open-ended stub and a 165-GHz traditional third-order quarter-wavelength shunt-stub filter.