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To cover the working frequency bands of the three mobile carriers of China Mobile, China Telecom, and China Unicom, power amplifiers (PAs) are required to own broadband. A PA with bandwidth 1.3–2.7 GHz is designed (fully covers the operating bands of the three mobile carriers). Measured results show that greater than 68% efficiency is attained over a 75% bandwidth from 1.3 to 2.7 GHz. The output power is larger than 40.2 dBm with gain varying from 10 to 13 dB across the band. In this article, three-frequency point matching method is applied in order for broadband matching. High-efficiency is achieved by a specially designed impedance matching topology which realizes short-circuits of the second harmonics and open-circuits of the third harmonics at different frequencies. The designed broadband high-efficiency GaN PA provides a new approach and method for the development of PAs in 4G base stations.

The design, implementation, and measurements of a high efficiency and high power wideband GaN HEMT power amplifier are presented. Package parasitic effect is reduced significantly by a novel compensation circuit design to improve the accuracy of impedance matching. An improved structure is proposed based on the traditional Class-F structure with all even harmonics and the third harmonic effectively controlled, respectively. Also the stepped-impedance matching method is applied to the third harmonic control network, which has a positive effect on the expansion bandwidth. CGH40025F power transistor is utilized to build the power amplifier working at 0.8 to 2.7 GHz, with the measured saturated output power 20–50 W, drain efficiency 52%–76%, and gain level above 10 dB. The second and the third harmonic suppression levels are maintained at −16 to −36 dBc and −16 to −33 dBc, respectively. The simulation and the measurement results of the proposed power amplifier show good consistency.

In this work, the modelling of composite right/left-handed transmission line and the CRLH transmission line theory have been studied. Then a parametric study of this components on YIG (with and without field) has been driven. Both experimental and simulated scattering parameters are shown, and the corresponding propagation constants are given, that enables to identify the different frequency bands: left-handed band, right-handed band and bandgap. This non-reciprocal metamaterials has potential to be used in radio frequency integrated circuits.

In this work, a tunneling magnetic flux controlled memristor emulator is presented. It imitates the behavior of the memristor with off-the-shelf solid state components. Two current conveyors, a multiplier, an IC with four operational amplifiers and several lumped-components are employed in the emulator. The two terminals of the emulator is float. The measured results with periodic unbalance input voltage are consistent with the SPICE simulation ones. The emulator provides an alternative solution of memristor model in real circuit applications.

That the high technology is applied in modern fire control system makes its performance improve greatly. Meanwhile the complexion of system structure and signal relationship increases the difficulty when testing it. Distributed testing network is presented for designing a set of simulation fire control system based on CAN bus in paper. All imitations of equipment units are linked by CAN bus, which can construct entire signal surrounding for equipment units to be tested. Simulation components is realized by means of industrial computer or sensor on the ground of the complexity of the equipment units accordingly.

To get a rapid estimation of the user's indication position in computer vision based noncontact human-computer interaction (HCI) system, an indication position estimation method without explicitly calculating the cameras' parameters. The homography matrix is calculated using the known points on the target plane and their corresponding points imaged by the cameras. By this homography relationship, the two lines which intersect at the indication point on the target plane are related with their corresponding lines on the image plane, thus the position of the indication point is estimated by detecting specific lines from images. Experimental results show that the average error of the homographic mapping is 0.726mm at the distance of 2.5m; meanwhile, the amplitude of errors rises by 2.6% from the center to the fringe of the screen (size of the screen is 2500mm×1800mm). The precision and consistency of this method can satisfy the requirement of most applications in human-computer interaction.

We report an enhancement-mode InAlN/GaN MISHEMT with a low gate leakage current by a thermal oxidation technique under gate. The off-state source-drain current density is as low as ~10−7 A/mm at VGS = 0 V and VDS = 5 V. The threshold voltage is measured to be +0.8 V by linear extrapolation from the transfer characteristics. The E-mode device exhibits a peak transconductance of 179 mS/mm at a gate bias of 3.4 V. A low reverse gate leakage current density of 4.9 × 10−7 A/mm is measured at VGS = −15 V.