Jordi Verdu

In this article, a novel exploration algorithm for the design and optimization of matching networks (MNs) in power amplifiers (PAs) is presented. The methodology is based on the automatic generation and optimization of both input and output MNs (IMNs/OMNs) according to a set of design rules and constraints that ensure technological feasibility. All candidate MN topologies are optimized and ranked using a unified cost function, enabling the automatic selection of the most suitable solution while facilitating a comprehensive tradeoff analysis among key performance metrics such as power-added efficiency (PAE), gain, bandwidth, physical size, and expected yield. As a result, the designer obtains a global view of the solution space and can objectively compare different MN configurations within a consistent optimization framework. To validate the proposed algorithm, a PA covering 1.1–1.9 GHz—fully encompassing the Galileo navigation bands E5, E6, and L1—and targeting high efficiency with harmonic control, was designed, fabricated, and experimentally characterized.

One of the major obstacles in network synthesis is the challenge of leading with a dispersive impedance at the input/output port, especially in acoustic wave (AW) multiplexers where antennas, switch modules, or active devices exhibit frequency-dependent behavior. This letter introduces an analytical synthesis method that extends conventional formulations of fully canonical (FC) ladder-type filters and multiplexers to accommodate a dispersive source impedance. By iteratively solving rational-function relations, the proposed method accurately captures the effects of dispersive impedance and adjacent-channels loading, if they exist while maintaining numerical stability. Two synthesis examples are presented to demonstrate the method’s effectiveness.

This work presents a synthesis methodology for Double-Mode Surface Acoustic Wave (DMS) filters linking reactance-level synthesis with the physical behavior of the structure. By combining the Coupling-of-Modes (COM) model with trisection and extracted-pole topologies, the method provides a direct mapping from coupling matrix (CM) parameters to geometric variables such as the IDT gap L_T, grating pitch P_m, and aperture W. A key contribution of this work is the explicit connection established between the synthesis formulation and the physical geometry of the DMS structure, enabling a clear interpretation of how geometric parameters—particularly the IDT gap and aperture—govern the resulting filter performance. The methodology further enables the incorporation of gradient-based optimization tools, yielding reproducible and robust designs, and supports fine-tuning for manufacturability to ensure practical layouts while preserving the desired transmission response. Validation is demonstrated through simulations and experimental measurements for a 605 MHz stand-alone filter fabricated on 42°Y-cut LiTaO₃, where synthesized, COM-simulated, and measured responses show good agreement for the baseline implementation. The approach enables reproducible and physically interpretable DMS designs adaptable to a wide range of bandwidth requirements.

This work presents the design and fabrication of a narrowband, fully canonical, fourth-order monolithic filter with fourth transmission zeros (TZs) operating in the S-band. The device is based on dielectric resonators made of barium titanate (BaTiO₃) ceramics. The TE₁₁₀, TE₁₂₀, and TE₂₁₀ modes are employed to generate the poles and TZs. The resonant frequencies are tuned by modifying the chamfer lengths at opposite corners of the square resonator. The coupling between cavities is implemented through an iris structure strategically arranged to fully exploit the capabilities of the degenerate dual modes. The experimental results show excellent agreement with the simulations.

This work proposes a synthesis method for high-order acoustic wave (AW) multiplexers with any manifold configuration, focusing on enhancing numerical stability while minimizing design execution times. The synthesis method is crucial for efficiently analyzing multiplexer floor plan in a short time (up to 90 possible configurations for herringbone hexaplexers), enabling rapid exploration of design alternatives and optimizing performance for complex RF module applications. The proposed approach reformulates the synthesis process towork primarily with polynomial roots rather than coefficients, leveraging the Durand-Kerner (DK) algorithm for efficient root computation. Additionally, a strategy to map polynomial roots to a less compressed domain is introduced, reducing numerical noise. The method involves computing the polynomial representation of a multiport network with fully canonical channels and deriving a set of K distorted channel polynomials, from which each AW ladder filter is synthesized independently. This methodology ensures the desired multiplexer response without channel loading degradation, allowing independent adjustment of return loss (RL) and transmission zeros (TZs) for each channel. It facilitates the design of multiplexers that meet the technological requirements of AW technology, including electromechanical coupling coefficient (k² _eff) and area efficiency, among other parameters. This approach avoids intensive optimization, representing a useful and controlled technique for designing advanced multiplexer filter modules.