The accurate comparison (or calibration) of conventional solid-state noise sources is often thought to be a difficult process that only specialized laboratories can perform. In this paper, the uncertainties due to the impedance differences between the sources and their on and off states are emphasized and a simple formula is developed that makes them negligible. It requires an isolator being used in front of the receiver. In the experimental section, the errors associated with common practice are evidenced and compared to what can be achieved through the correction formula.

In this paper, the basic quadratic form of the poly-harmonic distortion model is first presented and this is then extended to provide a new, modified quadratic poly-harmonic distortion model. Comparisons between the X-parameter model, the basic quadratic poly-harmonic distortion model, and the modified version are provided. Both simulation and experimental test results show that the new modified model provides significant improvements in accuracy, not only for the fundamental frequency, but also for DC. Work on the optimization of the model is also presented, providing further improvements in both the model extraction time and the file size.

A MMIC double-balanced subharmonic diode ring mixer was designed for broadband satellite communications exploiting a GaAs pHEMT process. The circuit implements the frequency conversion from Q (43.5–50 GHz) to Ku-K band (17–21.5 GHz). Besides the RF, LO, and IF baluns, the MMIC integrates a buffer amplifier for the local oscillator signal, which is designed between X and Ku bands (11–16.5 GHz), due to the subharmonic operation. The mixer measured conversion loss is between 8 and 12 dB along the bandwidth, with an LO power of 9 dBm. The input p1 dB and IP3 are 2 and 15 dBm, respectively. The balanced structure ensures an LO and 2 × LO leakages at the IF port lower than −25 and −35 dBm, respectively. Other spurious remain below −67 dBc. The chip dimensions are 2.4 × 2.4 mm2.

In this paper, the designs and experimental performances of wideband (higher than one octave) high-efficiency, high-power amplifiers (HPA) working in the 1–4 GHz range, using the same GaN process, are presented. They are based on the Bode–Fano integrals, which can be applied to a trade-off calculation between bandwidth and efficiency. Firstly, an microwave intregrated circuits (MIC) wideband HPA, externally matched, is presented. It generates a continuous wave (CW) output power (Pout) greater than 40 W, a power gain (GP) higher than 9.2 dB and a corresponding power added efficiency (PAE) (drain efficiency (DE)) ranged between 36 and 44% (40 and 48%) over the 1–3 GHz bandwidth. Two other amplifiers have been designed upon the same theoretical methodology, with a passive GaAs MMIC circuit technology, enabling to reduce the final size down to 420 mm2. The first internally matched Quasi monolithic microwave intergrated circuits (Quasi-MMIC) single-ended HPA generates a pulsed Pout greater than 25 W, GP higher than 9.8 dB, and a corresponding PAE (DE) ranged between 37 and 52.5% (40 and 55%) over the 2–4 GHz bandwidth. The second internally matched Quasi-MMIC HPA, based on balanced architecture, generates a pulsed Pout higher than 45 W, GP higher than 9.5 dB and PAE (DE) ranged between 33 and 44% (38 and 50%) over the 2–4 GHz bandwidth. These results are among the best ones published in terms of PAE and Pout in instantaneous octave bandwidth in the 1–4 GHz frequency range.

A novel compact ultra-wideband (UWB) eight-way ring-cavity power divider is presented in this paper. To broaden the bandwidth of the power divider/combiner, the stepped-impedance technology is used to realize the impedance match. The network of this eight-way ring-cavity power divider has been analyzed. The measured results reasonably agree with the simulated ones. The measured return loss is greater than 10 dB from 5.2 to 18.6 GHz. The average insertion loss, amplitude imbalance, and phase imbalance are around 9.4 dB (including the 9-dB power-dividing insertion loss), ±0.7 dB, ±6°, respectively, across the entire operating frequency range.

A new technique to realize quasi-elliptic bandpass filters with extreme close-in rejection is presented in this paper. The basic idea consists of embedding non-resonating mode waveguide cavities within the structure of an evanescent-mode filter. Such a combination of cavities and resonators allows the generation of very close transmission zeros while realizing at the same time relatively wide passbands and stopbands. Both H-plane TE201 mode and E-plane TM110 mode configurations are used as non-resonating mode waveguide cavities. In contrast with the other elliptic evanescent-mode filters using conventional approaches, the insertion loss degradation at the filter cut-off frequencies is minimized thanks to the high-Q factor of the waveguide cavities, whose corresponding poles are located right at the edges of the passband. The experimental results of an evanescent-mode filter having 9.950–11.000 GHz passband and providing more than 45 dB rejection between 11.040 and 11.050 GHz validate the proposed solution.

We present the results obtained on a multi-mode multi-band 20 W Monolithic Microwave Integrated Circuit (MMIC) power amplifier. The proposed two-stage circuit is based on the silicon Laterally Diffused Metal Oxide Semiconductor (LDMOS) technology. Thanks to dedicated design techniques, it can cover the Digital Cellular Service (DCS), Personal Communications Service (PCS), and UMTS bands (ranging from 1.805 to 2.17 GHz) and deliver more than 20 W of output power, 30 dB of gain and 50% of power added efficiency. When combined in a Doherty configuration with an incremental 40 W MMIC in a dual-path package, the resulted asymmetric MMIC (an industry first) can deliver an unprecedented LDMOS MMIC efficiency of up to 44% at 8 dB back-off in the UMTS band. Then, the DPA has been optimized in conjunction with a novel RF pre-distortion technique, leading to 33–80% energy saving at the system level.

This paper presents the analysis and design of a wideband asymmetrical Doherty amplifier. The frequency response of the output combining network of the Doherty amplifier with arbitrary back-off level configuration is analyzed. Other bandwidth-limiting factors were discussed and analyzed as well. A number of performance enhancement techniques were taken into consideration to obtain high and flat back-off efficiency over the amplifier design band of 1.7–2.25 GHz. The designed Doherty amplifier had, at 8.0–9.9 dB output back-off, a minimum efficiency of η = 50% [power-added efficiency of 45%], measured near 40 dBm of output power, and over 28% bandwidth. Using digital predistortion (DPD) linearization, an adjacent-channel leakage ratio (ACLR) of −43 dBc was obtained for a single-carrier W-CDMA signal, at 40.9 dBm and 46% of average output power and drain efficiency, respectively. The designed amplifier represents the first wideband Doherty amplifier reported over extended power back-off range.

A 24 GHz low-power transceiver is designed, fabricated, and characterized using 130 nm complementary metal-oxide semiconductor (CMOS) process. The designed transceiver is targeted for frequency-modulated-continuous-wave (FMCW) wireless local positioning. The transceiver includes four switchable receiving channels, one transmitting channel and local-oscillator generation circuitries. Several power-saving techniques are implemented, such as switch channel and adaptive mixer biasing. The design aspects of the low-power circuit blocks and integration considerations are presented in details. The integrated transceiver has a chip area of only 2.2 mm × 1.7 mm. In transmitting mode the transceiver achieves an output power of 4 dBm and phase noise of −90 dBc/Hz at 1 MHz, while consuming 75 mW power consumption under 1.5 V power supply. In switch-channel receiving mode the transceiver demonstrates 31 dB gain and 6 dB noise figure with 65 mW power consumption. The transceiver measurements compare well with the simulated results and achieve state-of-the-art performance with very low-power consumption.

A microwave rectifier at 5.8 GHz without any capacitors is presented, which owns a measured MW-to-DC conversion efficiency of 68.1%. A harmonic rejection filter and a DC pass filter, which replace lumped capacitors in conventional microwave rectifiers, are applied to suppressing the harmonics produced by an HSMS-286 Schottky diode during rectifying. At the fundamental frequency, a microstrip impedance transformer which contains a shunt λg/8 short-ended microstrip transmission line and two short series microstrip transmission lines are applied to compensating the imaginary impedance of the diode and matching the input impedance of the rectifier. The measured MW-to-DC conversion efficiency agrees well to the simulated results. The novel rectifier without any lumped passive elements may be applied for power transmission system at higher microwave frequencies.

A new quad-band bandpass filter for Global System for Mobile Communications, Wireless Local Area Network, and Worldwide Interoperability for Microwave Access is designed and fabricated using the stub-loaded resonator (SLR) technology without complex fabrication process, such as via-hole or multi-layer substrate. Owing to the embedded SLR, the proposed quad-mode resonator is compact. Equivalent circuits of the proposed quad-mode resonator are analyzed in detail, and high design freedom is shown because of shifting the passband frequencies individually. Good passband selectivity and isolation of the each passband at 1.8, 2.4, 3.5, and 5.2 GHz can be well achieved due to the transmission zeros appeared near the each passband edges. Experimental results show good agreement with the simulated results.

This paper introduces a VDD generator for the ultrahigh frequency (UHF) passive Radio-frequency identification (RFID) tag, consisting of an RF-limiter, an NMOS rectifier, a DC-limiter, and a regulator. The proposed NMOS rectifier utilizes diode-connected native NMOS transistors with ultralow-threshold voltage instead of Schottky diodes. The theoretical equations for predicting the performance of the VDD generator are provided and verified by both simulation results in 90 nm CMOS process. The proposed VDD generator generates a 1.19-V stable output voltage with low-power dissipation and a 26.96% larger power conversion efficiency under conditions of 50 Ω antenna, 900 MHz, −23 dBm input power and 1 M DC output load. The chip area of the proposed VDD generator is only 105 × 85 μm. The simulation results indicated that the presented novel VDD generator is capable to provide efficient, stable, and input-independent power supply for Passive UHF RFID tag

Microwave filters and multiplexers commonly employ tuning screws to compensate for small errors occurring during the fabrication process. Nevertheless, the use of tuning screws has some disadvantages, because the small gaps between the screws and the holes are prone to create unwanted effects when dealing with high-power signals, especially for space applications, and are also the source of potential radiation losses. In this paper, an alternative technique to correct manufacturing deviations is presented, in which tuning screws are replaced by fixed metal insertions. In this case, the correction is made by means of designing new insertion pieces that will be able to correct those small deviations. In order to find the dimensions of the new pieces, a space-mapping technique is applied. For verification purposes, the method has been applied over a circular-waveguide dual-mode filter and later over a manifold multiplexer containing the same type of filters. However, the technique can be directly extended to other types of waveguide filters and multiplexers where tuning screws are also employed.

Two novel memory polynomial models are derived based on physical knowledge of a general power amplifier (PA). The derivations are given in detail to facilitate derivations of other model structures. The model error in terms of normalized mean square error (NMSE) and adjacent channel error power ratio (ACEPR) of the novel model structures are compared to that of established models based on the number of parameters using data measured on two different amplifiers, one high-power base-station PA and one low-power general purpose amplifier. The novel models show both lower NMSE and ACEPR for any chosen number of parameters compared to the established models. The low model errors make the novel models suitable candidates for both modeling and digital predistortion.

A compact and broadband TE11-TE01-mode converter, suitable for various industrial applications like bypass level measurements, is presented in this contribution. Based on stepped waveguide technique, the main advantages of the recommended converter design and the specific field distribution of the TE01-mode are discussed in detail. The converter is presented exemplary for a frequency range from 23 to 28 GHz, which corresponds to a bandwidth of approximately 20 % of the center frequency. Numerous three-dimensional electromagnetic field simulations are performed to optimize the converter and to investigate its reflection and transmission behavior. Realized by six different single elements and 11 parts in total, fast and effective simulations can be performed with CST Microwave Studio. Considering realistic production process parameters, like fillets or tolerances, a good return loss better 17 dB, an insertion loss of 0.1 dB, and an excellent mode purity are achieved. Compared with back-to-back, realistic disturber scenario, and far-field measurements with a first prototype, the expected excellent converter behavior can be validated without limitations. Hence, the suitability of the presented converter design is proven and the feasibility is demonstrated.

In this paper, a fractal-based complementary split-ring resonator (CSRR) has been introduced as a defected ground structure (DGS) in the ground plane of a dual-mode microstrip bandpass filter to produce a new compact filter with dual-band response. The conventional double square ring resonator structure is modified such that its inner ring is made with a fractal shape instead of a square. Measured and simulation results show that the resulting filter offers a dual passband response; the higher passband is attributed to the dual-mode microstrip ring structure, whereas the lower passband is as a result of the embedded CSRR DGS structure. In addition, the results show that the position of the lower passband could be varied, to a certain extent, without affecting the position of the higher passband by applying higher fractal iteration levels to the inner split ring. These features, together with the compact size the proposed filter offers, make it suitable for use in a wide variety of dual-band communication applications. Measured results, carried out on filter prototypes, have been found in agreement with those theoretically predicted.

This paper presents the design fabrication and measurement of a nanogap radio frequency microelectromechanical system (RF MEMS) metal-contact switch. The prosed device generates a relatively high contact force with a low actuation voltage using a dielectric layer between the actuation electrode and the moveable beam. The actuation voltage is decreased with good reliability of the device by scaling down the gap. Beam geometry optimization allowed reaching 126 micronewtons contact force with only 10 V bias voltage. The fabricated miniature switch (80 × 50 × 0.95 µm) has indeed a pull-down voltage of 6 V and a contact resistance <2 Ω with 10 V bias applied. By measuring the S-parameters, the up-state capacitance has been fitted to 22 fF. The remarkable figure-of-merit Ron × Cup = 44 fs reflects the good performance of the device. A cycling test showed the device operated for 90 min without any charging problem noted.

In the field of high data rate wireless communications, localization issues play a key role in achieving energy-efficient communication and geographic routing. time-difference of arrival (TDOA)-based localization methods present numerous advantages. In this paper, a new method of TDOA estimation is proposed. With this method, unlike conventional TDOA measurements, it is possible to perform communication and localization at the same time by using a multi-input single-output system. By transmitting ultra-wide-band orthogonal frequency-division multiplexing signals using spatial diversity, it is possible to extract TDOA from interference patterns in spectral domain. In addition, increasing the precision of localization is also studied using a multi-band approach. This whole study is made within the framework of the WiGig alliance specifications; however, it is compatible with other standards.

A new ultra-high frequency radio frequency identification (RFID) tag antenna, which is comprised a U-shaped tuning stub and a dipole radiator for different permittivity surfaces is investigated, fabricated, and measured. For a conjugate match to the NXP G2XM chip impedance of 29–j137 at 915 MHz, a dipole tag antenna with U-shaped stubconnected to dipole arms was designed. Simple size adjustments of the U-shaped tuning stub and dipole radiator of the antenna allow for easy control of the antenna resistance and inductive reactance, from which the chip impedance requirement may be readily satisfied. The read range of the prototype antenna attached on a different permittivity surfaces (εr = 1–4) can reach more than 4.5 m, which has been tested for an RFID reader with 4.0 W of effective isotropic radiated power. The antenna structure consists of two dipole load bars and two loop electrically connected. The design offers more choice of freedom to tune the input impedance of the proposed antenna. Measurement data are presented which are in good agreement with simulation results. The design is suitable for mounting on all kinds of objects. The fabricated tag sensitivity of −3 dBm, read range of 7 m on the x–z and y–z planes, and the measured orientation radiation patterns were obtained in the desired frequency band.