Computer-aided design of impedance matching networks for RF applications

In this paper, we present a study on a transformer-based impedance matching network. We use a simplified transformer model comprising two magnetically coupled coils, which are driven by a source and terminated by a load. The formulae of the load and the source impedance for conjugate matching of both sides of the transformer are presented, and a figure of merit is proposed for the evaluation of the power transfer efficiency of the transformer under conjugate matching conditions. Analytical expressions are provided for constructing the widely used transformer network consisting of a resistive load and a parallel tuning capacitor. To verify the proposed work, we examined various on-chip transformers implemented in 0.18 μm CMOS technology. Simulation and measurement results for a matching network synthesized using the aforementioned analytical expressions corresponded well with the result of analysis for operating frequencies up to 72% of the self-resonant frequency of the transformer. The presented results confirm that the proposed analytical formulae based on the simplified transformer model are useful for the design and optimization of transformer-based impedance matching networks in the microwave and millimeter-wave regimes.

The architecture level design of an impedance matching network is presented for the global system for mobile communication radio frequency (GSM RF) power amplifier module used in a typical cellular handset. Designs for the low and high output impedance of the power amplifier and 50 Ω antenna impedance are considered. Impedance matching network design is presented for a typical low output impedance (Z = 2-j*0.4 Ω) of the power amplifier and 50 Ω antenna impedance and is made adaptive for high output impedance (Z = 7+j*2 Ω). It is shown that the network can be made adaptive to varying output requirements of the power amplifier by tuning the network capacitance toward the antenna end. The architecture level design of a 25 Ω antenna impedance is also presented and shown that that the impedance matching network can be made adaptive, which would require the use of MEMS switches. The adaptive impedance matching networks can be implemented in a passive integration technology with post-processing for MEMS components.

In the recent couple of decades, some multifunctional spaceborne active radars had been launched. Those radars used to be broadband radars using dipole transmitting antennas. The odd‐order resonant frequency of the antenna does not completely cover the operating frequency of the entire radar, so this may cause the antenna's radiation efficiency to deteriorate. The typical method to solve this problem was to design an impedance matching network system for broadband antennas to achieve a good voltage standing wave ratio and transmit power gain. In this paper, a new optimized real‐frequency method was designed, and a 0.4‐meter dipole antenna was tested before and after impedance matching. The measured results showed that the impedance matching network obtained by the optimized real‐frequency method proposed in this paper can improve the antenna radiation efficiency, and can effectively reduce the standing wave ratio to avoid damage to the transmitter caused by high echo power.

Comparison of a genetic algorithm to grammatical evolution for automated design of genetic programming classification algorithms

Underwater acoustic communication is a rapidly growing field of applied research and is a technique of sending and receiving message below water. There are several ways of doing such communication but the most common one is realized by using transducers. In underwater acoustic communication, one of the most important problems is driving the transducers with matched network. In this study, design of impedance matching network for B&K 8104 hydrophone that can be used for underwater communication was performed via Direct Computational Technique (DCT).

A circuit schematic for radio frequency (RF) impedance transformation is designed at first; then the elements in the schematic constitute a binary tree. Next the operation expression for impedance transformation is generated from the binary tree. The impedance transformation trace generation algorithm is proposed at last. In the last part of the paper a practical RF amplifier’s impedance matching network is simulated and analyzed to verify the algorithm. It can be seen that the algorithm is precise and efficient. This algorithm suggests applications to simulation and design of impedance matching networks for RF amplifiers.KeywordsSmith chartBinary treeWireless communicationImpedance transformation

The present paper derives a fast recursive least squares algorithm for the design of impedance matching network to any complex termination. Starting from any non-zero initial values, and for any topology, the network components are derived iteratively in a manner that optimizes the network's insertion loss characteristics. The strategy used is to minimize a weighted sum of the error between ideal time response and the network's time response. The main feature of the proposed technique is its very quick convergence, as it involves time computation at very small number of points. Besides, the proposed method has the flexibility of incorporating any frequency domain characteristics in the objective function to he minimum.

Harmonic rejection ability and reflection coefficient are the most important factors in the design of impedance matching network. However, stability of impedance matching should be taken into account in applications existing load impedance variation and component deviation due to tolerance and process variation. This paper investigates variability of Pi network impedance matching analytically. The relationships between resulting reflection coefficient with component deviation and load impedance variation are theoretically derived on the basis of Q-based design method. The deviation from perfect match due to component deviation is proportional to quality factor. Higher quality factor probably means poorer quality in terms of variability. The resulting reflection coefficient caused by load impedance variation increases rapidly when the load reflection coefficient is larger than 0.66. A small variation in the load impedance will cause a large deviation from perfect match when the impedance difference between load and source is quite large.

This technical paper presents a design and study of impedance matching for RF (radio frequency) circuit application of common-source amplifier topology. Input and output matching networks of the amplifier were designed and computed ensuring unconditional stability. Inductors and capacitors are key passive components that are crucial for impedance matching, and are specifically designed such that they would satisfy the gain requirements at a specific frequency of operation. Impedance matching is necessary in RF circuit design to provide maximum possible power transfer between the source or the generator and the load. Complex tradeoffs among technology specifications and design parameters exist and should be carefully handled when designing the impedance matching networks, to optimize the performance of the amplifier.Â

The use of automated optimisation in engineering applications is emerging. In particular, nature inspired algorithms are frequently used because of their variability and robust application in constraints and multi-objective optimisation problems. The purpose of this paper is the comparison of four different algorithms and several optimisation strategies on a set of seven test propellers in realistic industrial design setting. The propellers are picked from real commercial projects and the manual final designs were delivered to customers. The different approaches are evaluated and final results of the automated optimisation toolbox are compared with designs generated in a manual design process. We identify a two-stage optimisation for marine propellers, where the geometry is first modified by parametrised geometry distribution curves to gather knowledge of the test case. Here we vary the optimisation strategy in terms of applied algorithms, constraints and objectives. A second supporting optimisation aims to improve the design by locally changing the geometry, based on the results of the first optimisation. The optimisation algorithms and strategies yield propeller designs that are comparable to the manually designed propeller blade geometries, thus being suitable as robust and advanced design support tools. The supporting optimisation, with local modification of the blade geometry and the proposed cavity shape constraints, features particular good performance in modifying cavitation on the blade and is, with the AS NSGA-II (adaptive surrogate-assisted NSGA-II), superior in lead time.

High-intensity focused ultrasound (HIFU) has recently won wide recognition as a noninvasive treatment for many clinical applications. HIFU can ablate tissue at predetermined spot through accurate and stable output of acoustic power. Real-time power measurement is required for output characterization of driving electronics in most clinical HIFU systems. The measured power is also used to obtain voltage standing wave ratio (VSWR), which can reflect the change of transducer impedance induced by aging or temperature drift. However power measurement is still lacked in numerous pre-clinical or lab-level HIFU systems due to the cost and/or the complexity of integrated power meter. Additionally few work about power measurement have been reported. In this study, a power monitor is designed and constructed to be integrated into HIFU systems for power measurement. The developed power monitor is composed of a dual directional coupler, a power detector and two analog-to-digital converters. It is calibrated by the power meter at four frequencies (0.1, 0.5, 1 and 2 MHz) using linear least-squares fitting, and the measurement error is assessed for different powers at the previous four frequencies after calibration. Both functions of power measurement and VSWR detection are test through two transducers with and without impedance matching networks (IMNs). The post-calibration error is at most 10% with the power lower than 15 W whereas it is reduced to 2% after increasing power. The test results demonstrate that the developed power monitor is able to measure the power delivered to the transducer during sonications. Besides, it is an independent but cost-effective module for VSWR detection in the design of IMNs.

This paper presents design and simulation of an impedance matching network for GPS using embedded capacitor material which can substitute conventional matching network implemented by discrete lumped devices. The matching networks with ideal devices and commercial Panasonic discrete devices are simulated by ADS, and the one using embedded capacitor material is designed and simulated by 3D field solver software HFSS. The results of these three matching networks are discussed and compared together in a wide frequency band (0.1– 4 GHz) and a narrow frequency band (1.4–1.7 GHz). It can be seen that the electrical performance of matching network designed with embedded capacitor material is closer to ideal, and better than the one which using Panasonic discrete devices.

ObjectiveThe integration of artificial intelligence (AI) into CAD/CAM workflows has revolutionized dental prosthetics manufacturing, yet its morphological trueness compared to manual design remains underexplored.Materials and methodsThis study evaluated 30 single-tooth restoration cases from 30 patients. For each case, the original clinically-approved designs were used as reference. AI designs (3Shape Automate) were compared to manual designs created by a technician (3Shape Dental System™). Morphological trueness was evaluated through 3D deviation analysis. Global surface deviations (RMSE) were compared using the Wilcoxon signed-rank test, and maximum discrepancies were compared with a paired Student’s t-test, with significance set at p < 0.05.ResultsWhile AI demonstrated batch-processing efficiency, 6.7% of cases (2/30) with suboptimal preparation geometries required manual intervention. No significant difference was found in global surface deviation between AI (median = 79.8 μm) and manual designs (median = 68.6 μm; p = 0.1056). However, AI designs produced significantly greater maximum discrepancies (mean = 225.0 μm) compared to manual designs (mean = 184.4 μm; p = 0.0243).ConclusionThese findings validate AI’s viability for routine restoration design but emphasize the necessity of case selection protocols and algorithm improvements for dynamic occlusion modeling to ensure comprehensive clinical adoption.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12903-025-07004-z.

Harmonic rejection ability and reflection coefficient are the most important factors in the design of impedance matching network. However, stability of impedance matching should be taken into account in applications existing load impedance variation and component deviation due to tolerance and process variation. This paper investigates variability of T network impedance matching analytically. The formulas for calculating the resulting reflection coefficient caused by parameter variations are derived from quality factor-based design method. The analysis results can provide reference for design process and an opportunity for a better understanding of the dynamic behavior of the narrowband impedance-matching networks.

Design and verification of Self-Stabilizing (SS) network protocols are difficult tasks in part because of the convergence property that requires an SS protocol to recover to a set of legitimate states from any state in its state space. Once an SS protocol reaches a legitimate state, it remains in the set of legitimate states as long as there are no faults, called the closure property. Distribution issues exacerbate the design complexity of SS protocols as processes should collaborate and take local actions that result in global convergence. Most existing design techniques are manual, and mainly focus on protocols whose global state can be corrected if the local states of all processes are corrected, called the locally correctable protocols. After manual design, an SS protocol has to be verified for closure and convergence. Previous work observes that verifying SS protocols is a harder problem than designing them as developers have to ensure the correctness of closure and convergence functionalities and their noninterference. An algorithmic method for the design of convergence generates protocols that are correct by construction, thereby eliminating the need for verification. In order to facilitate the design of SS protocols, this article presents a lightweight method for algorithmic addition of convergence to finite-state nonstabilizing protocols, including nonlocally correctable protocols. The proposed method enables the reuse of design efforts in the development of different self-stabilizing protocols. Moreover, for the first time (to the best of our knowledge), this article presents an algorithmic method for the addition of convergence to symmetric protocols that consist of structurally similar processes. The proposed approach is supported by a software tool that automatically adds convergence to nonstabilizing protocols. We have used the proposed method/tool to automatically generate several self-stabilizing protocols with up to 40 processes (and 3 40 states) in a few minutes on a regular PC. Surprisingly, our tool has synthesized both protocols that are the same as their manually designed versions as well as alternative solutions for well-known problems in the literature (e.g., Dijkstra’s token ring, maximal matching, graph coloring, agreement and leader election in a ring). Moreover, the proposed method has helped us detect a design flaw in a manually designed self-stabilizing protocol.