Eric Kerherve

A new family of all-inductive dual-mode filters

In this paper, we describe a new family of dual-mode filters that is based on the use of simple inductive discontinuities in a rectangular waveguide environment. The proposed filter structure can be analyzed and optimized very efficiently using multimode equivalent network representations, thus leading to a simple and rapid development procedure. In addition to theory, the measured performance of a number of filter structures is also presented, thereby fully validating the proposed filter concept.

Modeling and Characterization of On-Chip Transformers for Silicon RFIC

A broadband and scalable lumped-element model for silicon on-chip transformers is presented. Model elements are driven from layout and process technology specifications. We provide simple and accurate expressions for evaluating the self inductance and the mutual coupling coefficient. The effects of various layout parameters, including transformer area, number of turns, and turns ratio, on transformer electrical response have been investigated. Model accuracy is demonstrated by comparing simulated and measured S-parameters, minimum insertion loss, quality factor, coils inductance, and magnetic coupling of several transformers with a wide range of configurations

A reconfigurable RF power amplifier biasing scheme

A reconfigurable power amplifier (PA) is studied in this paper, dedicated to multi-mode, multi-standard radio frequency front-end (RFFE), from a low cost approach. The reconfigurable amplifier topology is presented, made up of two-stages independently controllable by the biasing scheme proposed which allows the dynamic modification of the quiescent current of the RF transistor, to adapt both its linearity and its output power in order to fulfill different standards specifications.

Bulk acoustic wave coupled resonator filters synthesis methodology

This paper presents a synthesis methodology applied to bulk acoustic wave coupled resonator filters (BAW CRF). BAW-CRFs are able to realize wider bandwidth and higher rejection filter responses, but they present smoother roll-off coefficients compared to classical ladder topology. The proposed methodology enables to determine the filter structure dimensions able to synthesize Chebyshev responses. Finally, we address the design of an RF filter applied to the W-CDMA system employing the proposed methodology.

Design of broad-band matching network with lossy junctions using the real-frequency technique

A computer-aided design (CAD) procedure based on the real-frequency technique (RFT) is introduced for treating the matching of an arbitrary load to a complex generator. In this paper, the method has been applied to the design of interstage matching networks for microwave active circuits. The RFT provides several advantages over most of the usual techniques. It requires neither any transistor model because it directly includes measuring scattering- and noise-parameter data, nor a predetermined matching-circuit topology is necessary. A low-noise amplifier (LNA) design proceeding directly from experimental data is presented. Moreover, a new idea for treating the broadband matching problem leads to the use of an equalizer topology containing cascaded transmission lines with lossy junctions. Thus, gain-flatness and stability are satisfied by designing the input and the output matching circuits by the line-segment technique. An example is presented for the matching of a 0.1-5 GHz amplifier.

A Novel Method for Synthesizing an Automatic Matching Network and Its Control Unit

We present a novel method simplifying matching network synthesis and design based on a tunable low-pass π matching network topology. This method exploits the Smith chart in a novel way. Analytic expressions for calculating the optimal matching network for automatically adapting the load to the source impedance are derived. This work is applied to a new antenna tuning unit concept able to calibrate the system in a single iteration process reducing strongly both the speed and the overall consumption of the antenna calibration module. The obtained matching network nodal and load quality factors are analyzed and the matching network efficiency is evaluated to highlight the impact of the imperfection in the design. The simulation and experimental results are presented to validate the proposed method and to evaluate the obtained matching efficWe present a novel method simplifying matching network synthesis and design based on a tunable low-pass π matching network topology. This method exploits the Smith chart in a novel way. Analytic expressions for calculating the optimal matching network for automatically adapting the load to the source impedance are derived. This work is applied to a new antenna tuning unit concept able to calibrate the system in a single iteration process reducing strongly both the speed and the overall consumption of the antenna calibration module. The obtained matching network nodal and load quality factors are analyzed and the matching network efficiency is evaluated to highlight the impact of the imperfection in the design. The simulation and experimental results are presented to validate the proposed method and to evaluate the obtained matching efficiency. We perform reflection coefficients less than -30 dB, high efficiency matching networks with only 258 μs to calculate the proper state of the tunable matching network under a processor delivering 40 MIPS of performance.iency. We perform reflection coefficients less than -30 dB, high efficiency matching networks with only 258 μs to calculate the proper state of the tunable matching network under a processor delivering 40 MIPS of performance.

An Analytical Broadband Model for Millimeter-Wave Transformers in Silicon Technologies

A lumped element model to represent the behavior of millimeter-wave (mm-wave) integrated transformers is presented. Details on the topology allowing efficient mm-wave operation are given. The model presents a 2- π architecture and contains the equations to evaluate its components values. These equations depend on both technological and geometric characteristics of the transformer. The model is validated through experimental data of a set of 65-nm CMOS and 130-nm BiCMOS transformers. A very close agreement is shown for both S-parameter and inductance values up to 110 GHz.

A 60GHz 65nm CMOS RMS power detector for antenna impedance mismatch detection

This paper presents a 60GHz 65nm CMOS RMS power detector to be used in a Power Amplifier regulation loop. The presented test-chip integrates also a differential capacitive coupler sensing the RF voltage on a differential transmission line. The circuit shows 25dB of linear detection range at 60GHz, well enough to cover a VSWR of up to 7∶1 caused by antenna impedance mismatch while still having 10dB margin for output power regulation. The detector consumes only 50µA from a 1.2V power supply and occupies an active area of 80×80µm2.

Linear-Phase Delay Filters for Ultra-Low-Power Signal Processing in Neural Recording Implants

We present the design and implementation of linear-phase delay filters for ultra-low-power signal processing in neural recording implants. We use these filters as low-distortion delay elements along with an automatic biopotential detector to perform integral waveform extraction and efficient power management. The presented delay elements are realized employing continuous-time OTA-C filters featuring 9th-order equiripple transfer functions with constant group delay. Such analog delay enables processing neural waveforms with reduced overhead compared to a digital delay since it does not requires sampling and digitization. It uses an allpass transfer function for achieving wider constant-delay bandwidth than all-pole does. Two filters realizations are compared for implementing the delay element: the Cascaded structure and the Inverse follow-the-leader feedback filter. Their respective strengths and drawbacks are assessed by modeling parasitics and non-idealities of OTAs, and by transistor-level simulations. A budget of 200 nA is used in both filters. Experimental measurements with the chosen filter topology are presented and discussed.

A High Isolation and High Selectivity Ladder-Lattice BAW-SMR Filter

This paper presents a BAW-SMR filter using a combined ladder-lattice topology for application in W-CDMA reception front-ends (2.11 - 2.17 GHz). The combined topology allies the advantages of both network types, having very steep responses and high isolation at undesired bands. The design of filter was simulated using a combined 2D EM-acoustical analysis procedure, it presents: 1.6 dB of insertion loss, -10 dB of return loss and isolation higher than -48 dB at TX band (1.92 - 1.98 GHz)