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This comprehensive, hands-on review of the most up-to-date techniques in RF and microwave measurement combines microwave circuit theory and metrology, in-depth analysis of advanced modern instrumentation, methods and systems, and practical advice for professional RF and microwave engineers and researchers. Topics covered include microwave instrumentation, such as network analyzers, real-time spectrum analyzers and microwave synthesizers; linear measurements, such as VNA calibrations, noise figure measurements, time domain reflectometry and multiport measurements; and non-linear measurements, such as load- and source-pull techniques, broadband signal measurements, and non-linear NVAs. Each technique is discussed in detail and accompanied by state-of-the-art solutions to the unique technical challenges associated with its use. With each chapter written by internationally recognised experts in the field, this is an invaluable resource for researchers and professionals involved with microwave measurements.

Researchers at the University of Cantabria in Spain have designed and fabricated a phase switch for use in radio astronomy and other microwave measurement systems. Researcher Enrique Villa described the design of the team's device as a 90° hybrid design based on the use of microstrip bandpass filters. The coupling between the branches is achieved by a broadband MMIC single pole double through switch based on pseudomorphic HEMT transistors. Villa went on to say that taking into account they are based on short-circuited stub π-networks, the phase features of each filter are calculated, and the individual phase expressions enable us to obtain the phase dependence between filters and to consider it as a design parameter.

The effect of temperature on thermoelectric microwave power sensors is researched in order to extend its application field. The fabrication of this microwave power sensor is divided into a front side and a back side processing using GaAs MMIC process and MEMS technology. The measurement results show that the temperature has a significant effect on the performance of thermoelectric microwave power sensors. The obtained temperature coefficient is about 0.488 mV/(W · K), which has an important reference value for the thermoelectric microwave power sensors. The reason is that the accuracy of microwave power measurement will be realised as long as the environment temperature is tracked.

The authors design a cavity-backed Vivaldi antenna (CBVA) for microwave breast measurements. The design criteria for the antenna is shaped by the requirements of the free-space measurement scenario where the receiving and the transmitting antennas are rotated by a mechanical scanner. Later, the authors have performed various breast phantom measurements with the CBVA to reveal its feasibility for microwave tomography.

Microwave interferometry provides a sensitive measurement of amplitudes and phases of reflections. Basically, the interferometric system can be used to measure a non-electrical quantity, such as distance. Presented is a new method to evaluate data from a microwave interferometer. The method is compared with the previously used procedure. The new method provides more accurate results and also offers the possibility of self-calibration.

Potential applications of microwave energy, a developed form of clean energy, are diverse and extensive. To expand the applications of microwave heating in the metallurgical field, it is essential to obtain the permittivity of ores throughout the heating process. This paper presents the design of a 2.45 GHz ridge waveguide apparatus based on the transmission/reflection method to measure permittivity, which constitutes a system capable of measuring the complex relative permittivity of the material under test with a wide temperature range from room temperature up to 1100 °C. The experimental results indicate that the system is capable of performing rapid measurements during the heating process. Furthermore, the system is capable of accurately measuring dielectric properties when the real part of the permittivity and the loss tangent vary widely. This measurement system is suitable for high-temperature dielectric property measurements and has potential applications in microwave-assisted metallurgy.

This unique first-of-its-kind resource provides practical coverage of the design and implementation of frequency measurement receivers, which aid in identifying unknown signals. The technologies used in frequency measurement interferometry-based on-delay lines and filters are explored in this book. Practitioners also find concrete examples of microwave photonics implementations. The designs and concepts that cover conventional photonic instantaneous frequency measurement (IFM) circuits are explained. This book provides details on new designs for microwave photonic circuits and reconfigurable frequency measurement (RFM) circuits using diodes and MicroElectroMechanical Systems (MEMS). This book explains the many diverse applications of frequency measurement that are used in defense, radar, and communications. The instrumentation used to perform frequency measurements is explained, including the use of block analysis for network and spectrum analyzers and calibration techniques. Readers learn the advantages of using frequency measurement based on microwave/RF techniques, including immunity to electromagnetic interference, low loss, compatibility with fiber signal distribution, and parallel processing signals. Moreover, readers gain insight into the future of frequency measurement receivers. The book examines both the underpinnings and the implementation of frequency measurement receivers using many diverse technological platforms.

Optical rectification of ultrafast laser pulses is widely used to generate THz radiation. Here, the microwave frequency comb generated by optical rectification with a ZnTe(100) crystal and a mode-locked ultrafast laser has been measured, showing that the harmonics are at integer multiples of the pulse repetition rate of the laser (500 Hz). Strong correlations of the peak powers of the simultaneously measured THz spectrum and the measurements of the microwave frequency comb near 7.5 GHz suggest that they have a common origin.

The state of an itinerant microwave field can be coherently transferred into, stored in and retrieved from a mechanical oscillator with amplitudes at the single-quantum level, and the time to capture and retrieve the microwave state is shorter than the quantum state lifetime of the mechanical oscillator. Mechanical oscillation and quantum state storage In the last decade it has become possible to control macroscopic mechanical oscillators in such a way that they show quantum behaviour. The next step is to exploit this capability to produce useful devices for quantum information applications, in particular as storage elements for quantum states, a role for which mechanical oscillators show promise. One way of achieving this is to embed mechanical oscillators in superconducting circuits where quantum information can be processed in the form of microwave fields. Tauno Palomaki et al . now reach an important goal in this area by showing that the state of a microwave field can be coherently stored in and retrieved from a mechanical oscillator at the single-quantum level. Macroscopic mechanical oscillators have been coaxed into a regime of quantum behaviour by direct refrigeration 1 or a combination of refrigeration and laser-like cooling 2 , 3 . This result supports the idea that mechanical oscillators may perform useful functions in the processing of quantum information with superconducting circuits 4 , 5 , 6 , 7 , either by serving as a quantum memory for the ephemeral state of a microwave field or by providing a quantum interface between otherwise incompatible systems 8 , 9 , 10 , 11 , 12 , 13 , 14 . As yet, the transfer of an itinerant state or a propagating mode of a microwave field to and from a storage medium has not been demonstrated, owing to the inability to turn on and off the interaction between the microwave field and the medium sufficiently quickly. Here we demonstrate that the state of an itinerant microwave field can be coherently transferred into, stored in and retrieved from a mechanical oscillator with amplitudes at the single-quantum level. Crucially, the time to capture and to retrieve the microwave state is shorter than the quantum state lifetime of the mechanical oscillator. In this quantum regime, the mechanical oscillator can both store quantum information and enable its transfer between otherwise incompatible systems.

This work presents the validation of a low-cost measurement system based on an open-ended coaxial SMA (SubMiniature version A) probe for the characterization of complex permittivity in the microwave frequency range. The system combines a custom-fabricated probe, a vector network analyzer, and a dedicated software application that implements three analytical models: capacitive, radiation, and virtual transmission line models. A comprehensive experimental campaign was carried out involving pure polar liquids, saline solutions, and biological tissues, with the measurements compared against those obtained using a high-precision commercial probe. The results confirm that the proposed system is capable of delivering accurate and reproducible permittivity values up to at least 6 GHz. Among the implemented models, the radiation model demonstrated the best overall performance, particularly in biological samples. Additionally, reproducibility tests with three independently assembled SMA probes showed normalized deviations below 3%, confirming the robustness of the design. These results demonstrate that the proposed system constitutes a viable alternative for cost-sensitive applications requiring portable or scalable microwave dielectric characterization.