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This paper presents a simple and universal measurement method for the average efficiency and instantaneous efficiency of pulsed RF power amplifiers. The average efficiency of the traditional definition varies with different duties and thus lacks universality, because of the DC power consumption outside the RF pulse. In our proposed method, the DC power consumption within a pulse period is divided into different parts. The parameters of each part can be extracted-from simple measurements of the average voltage and current under different duties. The average efficiency and instantaneous efficiency of different duties can be calculated with the extracted parameters. Since current clamps or oscilloscopes are not necessary to measure the instantaneous voltage and current, this solution can be easily implemented in a simple and cost-effective way, to expand the application into compact and sealed circuits. Measurement uncertainties under different duties were analyzed of the method. Experimental results of the proposed method are consistent with theoretical efficiencies, which help validate the method.

This paper describes a direct-conversion E-band transmitter (TX) in 65-nm CMOS. To demonstrate the feasibility of E-band 1024-quadrature amplitude modulation (QAM), a 67 to 86 GHz direct-conversion CMOS transmitter with broadband image rejection is presented. The transmitter contains an I (in-phase) and Q (quadrature-phase) modulator and a five-stage power amplifier. To achieve a 40 dBc image-rejection ratio (IRR) of the I/Q modulator for E-band, a broadband half-quadrature generator (HQG), which contains a composite right/left-handed (CRLH) based divider, quadrature couplers, and baluns is proposed. For the purpose of minimizing the phase imbalance, phase balance lines are utilized in HQG to achieve a 1-degree phase accuracy under different tuning lines. Subsequently, the reflection can be mitigated by optimizing the impedance matching between the HQG and the mixer core. Meanwhile, because millimeter-wave (MMW) circuits are susceptible to process variations, a process-variation-tolerant design is introduced to mitigate IRR variation, especially under 40 dBc. The transmitter demonstrates a measured flat conversion gain (CG) of 23±2 dB from 56 to 86 GHz. The proposed TX achieves an IRR better than 40 dBc from 67 to 86 GHz (bandwidth of 19 GHz) with a peak IRR of 56.2 dBc at 70 GHz. Furthermore, the proposed TX has exhibited a 6 bit/s/Hz spectral efficiency with 1024-QAM under the orthogonal frequency-division multiplexing (OFDM) modulation format. The 1.129 mm2~E-band TX achieves a measured output power of 6.5 dBm with a total dc power consumption of 164 mW from a 1.2 V supply voltage.

This paper presents two Ka-band calibration-free up/down mixers, each with high image rejection ratio (IRR) for a wide band of IF frequencies covering the satellite modem frequency range (0.95-2.15 GHz). To achieve broadband IRR > 30 dBc, a 3-stage castle-wall polyphase filter (PPF) is used at the IF port to minimize the amplitude and phase errors (AM 1dB) of 0 dBm. With a 1.2-V supply voltage, the SSB up mixer and IR down mixer consume 15.6 mW and 12 mW, respectively. The SSB up mixer and IR down mixer demonstrate broad IRR bandwidths at the IF frequencies (IRR > 30 dBc) from 0.6 to 4 GHz (148% fractional IF bandwidth) and from 0.65 to 2.5 GHz (117%), respectively, with no calibration. In addition, the RF bandwidths (IRR > 30 dBc) of the SSB up mixer is 27.7-33.3 GHz (18.36% fractional RF bandwidth), and the IR down mixer is 17.1-20.6 GHz (18.5%). The IRR performances are robust against process, voltage, and temperature (PVT) variations and Monte Carlo simulations for satellite communication (SATCOM) applications.

This paper presents a dual-polarization antenna with high spectral efficiency for transmission application distance at 60 GHz. The dual-polarization antenna is integrated with the receivers through flip chip on the LTCC substrate at 60 GHz. The receiver front-end composes of a low noise amplifier and demodulator fabricated in 65-nm CMOS process. The conversion gain is higher than 14 dB and the noise figure is lower than 6 dB from 57 to 66 GHz. The total data rate of the proposed system's spectral efficiency is up to 12 bit/s/Hz for wireless measurement and the EVM is below 5.5 %.

This paper addresses the problem of Cramér-Rao lower bound (CRLB) analysis for joint target location and velocity estimation in a multistatic passive radar system comprised of multiple noncooperative illuminators of opportunity (IOs) and multiple geographically separated receivers. Unlike other existing studies, special attention in this paper is paid to a more ubiquitous scenario, in which no reference channel exists in receiver networks. Besides, the situation where the measurements collected at the receivers are contaminated by the interference directly illuminated from the IOs is taken into account. Namely, each receive station simultaneously obtains direct-path interference (DPI) from all the IOs and echo signals reflected by the target. Furthermore, the IO waveform is modeled as a stochastic process in which samples of the unknown IO waveform are treated as a complex Gaussian sequence. Finally, the effects of multipath clutter on the signal model and CRLB are well analyzed. The numerical results are provided to prove that the joint CRLB is not only a function of the signal-to-noise ratio (SNR), DPI-to-noise ratio (DNR), and clutter-to-noise ratio (CNR) but also associated with both IO waveform parameters and relative geographical distribution of the system.

There is a strong demand for the research of electric vehicles (EVs) in automotive industry, because of an increased concern of the energy depletion and environmental pollution problems caused by oil-fueled automotive. The traction motor drive system is one of the core components of EVs, and a motor with superior dynamic performance and high efficiency could significantly reduce energy consumption and improve riding comfort of EVs. Therefore, in order to achieve high dynamic performance and high efficiency of permanent magnet synchronous motor (PMSM), a multi-objective optimization design method for PMSM based on the artificial bee colony algorithm was proposed in this paper. First, based on the magnetic field analytical model of PMSM, the analytical expressions of the key parameters were deduced, namely, mechanical time constant and electrical time constant. Second, the efficiency and electrical and mechanical time constant were defined as optimization objectives. Third, the efficiency and dynamic performance of the original motor and optimized motor were compared applying the finite-element analysis. Furthermore, one prototype machine was manufactured according to the results of optimization. The dynamic performance and efficiency of the prototype had been tested. The experiments show confident results that the efficiency increased about 1% and the mechanical time constant reduced to 31.4% of initial value.

Predictive speed control (PSC) is a promising control strategy for high dynamic performance electrical drives. However, its implementation faces two challenges: the selection of weighting factors and the elimination of steady-state errors (SSEs). The weighting factors are commonly selected through trial-and-error, which is time consuming. Additionally, SSEs are frequently observed due to model uncertainties and parameter mismatches. Focusing on the aforementioned issues, this article proposes a PSC strategy for surface-mounted permanent-magnet synchronous motor drives, where the weighting factors are designed algebraically and SSEs are eliminated. The weighting factor design process is illustrated through rearranging the equivalent speed tracking error. The SSEs are eliminated by incorporating integral terms into the cost function. The performance of the proposed strategy is validated through comparative experiments with field-oriented control and adaptive integral sliding-mode predictive control. The results demonstrate the effectiveness of the designed weighting factors and the robustness of the system. [ABSTRACT FROM AUTHOR]