Pedro de Paco

Equivalent circuit modeling of coupled resonator filters

Using the stacked crystal filter (SCF) concept, a coupled resonator filter (CRF) can be interpreted as a device in which 2 piezoresonators are stacked on top of each other in such a way that a certain degree of acoustic interaction occurs. The work presented in this paper reports a novel all-electrical model for the CRF. The model associates acoustical coupling with an equivalent electrical coupling between resonators. The resulting equivalent circuit makes it possible to apply classical filter synthesis techniques directly based on the coupling control between resonators. It complements with a synthesis approach the analysis approach of the Mason model.

DUAL-BAND FILTER USING NON-BIANISOTROPIC SPLIT-RING RESONATORS

This work proposes the use of Non-Bianisotropic Split Ring Resonators (NB-SRRs) as building blocks for dual-band response fllters. Design parameters will be evaluated in order to characterize coupling mechanisms for both the particle and fllter structure. A ready-to-use dual-band fllter for a multiconstellation Galileo/GPS global positioning receiver is manufactured in order to validate and test the proposed design. The device transmission response measurement agrees with both circuital and electromagnetic simulations, as well as with theoretical insertion losses, which are 2.4dB and 3.5dB at center passbands for L5 and L1 bands respectively.

PROCEDURE FOR THE DESIGN OF LADDER BAW FILTERS TAKING ELECTRODES INTO ACCOUNT

This paper aims to complete a published systematic methodology for the design of ladder BAW filters in order to include the effect of the electrodes, since infinitely thin electrodes are assumed in this design methodology. The new procedure is validated against the work of other authors, finding very good agreement between results.

A Dual-Band 180-Degree Hybrid Coupler Based on Coupled-Line Sections

This letter presents a novel 180 degree hybrid coupler structure based on coupled-line sections which offers a compact circuit and a dual-band operation. The structure is based on 90 degree and 180 degree coupled lines suitable to offer a 180 degree hybrid coupler behavior at two frequency bands when the even and odd impedances of the coupled-line sections are properly determined. The circuit presents a symmetry plane that enables an even/odd analysis. The dual-band operation of the structure has been verified by means of a prototype implemented in microstrip technology operating at 2.4 and 5 GHz.

IMPROVING SILICON INTEGRATED ANTENNAS BY SUBSTRATE MICROMACHINING: A STUDY OF ETCHING PATTERNS

One of the main drawbacks of antenna integration on standard CMOS silicon substrates are the low radiation e-ciency levels obtained due to the high silicon losses. This paper studies the use of micromachining techniques to remove silicon beneath the antenna as a solution to improve radiation e-ciency. Several etching patterns are analyzed for difierent etching depths through simulations and measurements in order to flnd out which are the best ones for the micromachining process. Results are verifled in two operating scenarios.

Design, fabrication and measurement of a GPS-Galileo dual-passband filter

This paper presents the design, fabrication and measurement of a GPS-Galileo dual-passband filter. The applied synthesis methodology is based on a frequency transformation of the Chebyshev low-pass prototype, and unlike most of conventional synthesis methodologies allows us to design dual-passband filters as classical coupled-resonator filters. The filter is designed and fabricated in microstrip technology which offers a very cost effective device with reduced size and weight. The measured insertion loss is about 2 dB in the lower band and 3.5 dB in the higher band. Lower insertion loss is possible using resonators with higher unloaded quality factor, for example cavity resonators, but on the other hand this type of resonators presents much higher cost, size and weight.

Design of a Coupled Resonator 3dB power divider based on BAW technology

Conventional power dividers based on quarter-wavelength lines are not adequate for the high level of miniaturization demanded for new wireless communications systems. The use of Bulk Acoustic Wave (BAW) technology overcomes the miniaturization issue. The design approach for an equal power divider based on BAW Coupled Resonator Filters (CRF) is introduced. A 3 dB power divider designed for W-CDMA receivers is presented. The proposed structure formed by three CRF sections shows a Chebyshev filtering response with 20 dB return loss. The designed CRF power divider simplifies the fabrication because almost all the multilayer films are uniform for all the CRF sections.

A dual-band resonator in Bulk Acoustic Wave technology

Filters with the capacity of operation in different frequency bands are important components in new multi-band wireless communication systems. The use of dual-band resonators is a possible mechanism to create the dual-band filter. In this paper, a novel dual-band resonator based in Bulk Acoustic Wave technology is proposed. Limitations in the dual-band resonator for designing dual-band filters have been studied. A Galileo/GPS dual-band filter in ladder-type topology is designed using the proposed dual-band resonator.

Direct Coupling Matrix Synthesis of Bandstop Filters

This work presents a straightforward way to obtain the coupling matrix of a bandstop flltering response from the original bandpass coupling matrix. The generated bandstop coupling matrix implements a response where the bandwidth is deflned at the equiripple return loss of the lower and the upper passbands.

Electric Equivalent Circuit for the Thickened Edge Load Solution in a Bulk Acoustic Wave Resonator

With the aim to improve the performance of Bulk Acoustic Wave resonators, the thickened edge load can be included on the top electrode. Using this solution, the energy trapping concept is forced, and lateral unwanted resonances are not present in the electrical behavior of the resonator. The way to design such a thickened edge load entails, on one hand, the presence of a resonant mode given by the thickened edge load; on the other hand, the degradation of the electromechanical coupling coefficient of the main thickness mode. In order to study the previous phenomena, the electric equivalent circuit has been developed. The obtained results have been validated with the three-dimensional simulations and compared with manufactured resonators.