O. Menendez

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.

Nonlinear performance characterization in an eight-pole quasi-elliptic bandpass filter

In this work we predict the nonlinear behaviour of an eight-pole quasi-elliptic bandpass high temperature superconducting (HTS) filter with an equivalent circuit extracted from intermodulation measurements performed at the centre of the filter passband. We present measurements that show that the equivalent circuit is able to predict the intermodulation products produced by the filter when driven by two in-band or out-of-band sinusoidal signals. Numerical techniques based on harmonic balance are used to extract the elements of the equivalent circuit and to simulate its nonlinear performance.

Branch-Line Coupler Based on Edge-Coupled Parallel Lines With Improved Balanced Response

A conventional branch-line coupler is flat-balanced, in terms of magnitude and phase, in a narrow frequency band due to the quarter-wave length requirement in the transmission lines. In this paper, a novel branch-line structure is presented in order to overcome this limitation. Loading the horizontal transmission lines with a pair of open-end series stubs, the magnitude and phase balance becomes flatter in a wider frequency range. However, the proposed structure cannot be fabricated, for which an equivalent circuit using edge-coupled parallel lines has been used. The measurement of this device shows a relative bandwidth of 82.5% for 2 dB magnitude and 72% for plusmn5deg phase balance condition.

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.

A Split-Ring-Resonator Loaded Monopole for Triple Band Applications

A monopole loaded with a split-ring resonator (SRR) will be presented for applications requiring efficient triple-band performance. The design is based on the principle of non-resonant traps and takes advantage of the dual-band behavior of the SRR. The mid-band frequency is mainly controlled by the dimensions of the monopole whereas the frequencies of the lower and upper bands are determined by the resonances of the SRR. As proof of concept, an antenna covering the universal 802.11 standard (2.4–2.5 GHz and 4.9–5.875 GHz) and the low band of the 802.15 standard (3.244–4.742 GHz) has been designed, fabricated and measured.

Nonlinear distortion in a 8-pole quasi-elliptic bandpass HTS filter for CDMA system

High Temperature Superconductor materials are known to produce intermodulation and other nonlinear effects which may restrict their use in wireless communication systems. Quantifying this degradation is crucial in determining if the use of HTS filters in the receiver is beneficial. In this work we use an approach for representing the HTS filter nonlinear equivalent circuit and simulating its performance. We have tested the approach on a planar, 8-pole quasielliptic (QE) filter, showing agreement between simulations and measurements of intermodulation products (IMD). The nonlinear equivalent circuit is then used to predict the nonlinear behavior of the filter and its effects on system parameters when it is subject to broadband signals like those used in wireless communication systems.

Dual-Band Mixer Using Composite Right/Left-Handed Transmission Lines

The concept of composite right left-handed transmission lines provides for one additional degree of freedom in realizing arbitrary dual-band frequency response devices. In this letter, an arbitrary dual-band operation mixer, based on the classical balanced mixer topology is proposed. The prototype demonstrates the mixer performance for a ratio of 2.5 between the two operation bands (860 MHz and 2,150 MHz). The conversion losses are better than 8.5 dB in both bands.

Closed-Form Expressions for the Design of BAW CRF Acoustic Inverters

A bulk acoustic wave coupled resonator filter is a device in which two thin film bulk acoustic wave resonators are stacked on top of each other separated by a set of passive layers which control the degree of acoustic interaction between resonators contributing to the conformation of the radiofrequency passband response. The set of passive layers implements an impedance inverter which has to fulfill the desired coupling value. The variation of the acoustic lengths of the coupling layers gives the degree of freedom to implement the desired inverter. In this work, a set of closed-form expressions are provided to obtain the coupling layers thicknesses without any time-consuming optimization procedure. The provided solution gives an explanation to the underlying fundamentals that take place in a successful optimization procedure.

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.

General equations for the induced phase shift in resonant electrooptic modulators

We derive general equations to calculate the electrooptically induced optical phase shift in resonantly enhanced modulators. The equations are useful in designing modulator electrodes with optimal length and optimal mismatch between electrical and optical velocities. We demonstrate the existence of an optimal velocity mismatch depending on the resonant mode used.