In this letter, we propose a methodology for designing high efficiency broadband harmonic-controlled power amplifiers (PAs) with a novel harmonic matching network. This network consists of three second-harmonic open circuit microwave lines and three third-harmonic short circuit microwave lines, each corresponding to different wavelengths for different frequencies. It can improve the efficiency and bandwidth of PAs by controlling harmonic match impedance. Through the proposed network, we design and fabricate a highly efficient broadband continuous Class-F PA using a CGH40010F GaN HEMT device. The measurement results show that the drain efficiency of 71.4% to 82.4% (the average efficiency of 76.9%) and output power of 40.4dBm to 42.6dBm are achieved at 1.3GHz-2.5GHz, respectively.

In this work, we have constructed an Erbium-doped fiber sigma laser (EDFσL) using a double-pass cascaded-chirped long-period fiber grating (C-CLPG) from the viewpoint of the sensor applications. The double-pass C-CLPG is composed of a C-CLPG and a Faraday rotator mirror (FRM) and works as a comb-like wavelength selection element as well as a sensor section in the sigma-branch of the laser cavity. Further, due to the FRM reflection scheme, the double-pass C-CLPG compensates for birefringence variation in the sigma-branch during the sensing. In the experiment, the sensor section near the C-CLPG is intentionally deformed to induce birefringence variation assuming the external disturbances; nevertheless, it is confirmed that the double-pass C-CLPG provides stable polarization states. Then, under the birefringence variation, it is demonstrated that the proposed EDFσL can achieve a stable oscillation and resultant precise measurements in contrast to the simple EDF ring laser using the single-pass C-CLPG. In addition, for the demonstration of the sensor with external force to the fiber, the oscillation wavelength of EDFσL in response to axial strain is investigated, and a linear response with sensitivity ∼0.32pm/µε is obtained.

In this paper, a novel power amplifier (PA) is proposed. An asymmetrical branch-line coupler is exploited as the output matching circuits of the proposed PA. Meanwhile, by setting the impedance conditions with trade-off in desired pass-band appropriately, impedance matching and output power combination can be realized in a single circuit. A brief analysis of the asymmetrical branch-line coupler is presented. Compared with the traditional high-power PAs design method, this design method can meet the requirement of the miniaturization. To prove the validity of the proposed method, a PA works at 2GHz is designed, fabricated and measured by using a 10-W gallium nitride (GaN) transistor (CGH40010F). The measured results show that a saturated output power of 42.8-45.2dBm with a power-added efficiency of 52.0-62.6% is achieved and a saturated power gain between 7.9 and 10.1dB.

This paper presents a novel thermal protection circuit for low dropout regulators (LDOs). To avoid thermal damage under high power conditions, the output current of LDOs varies with the sensed load temperature. Both the current delivery capability at a pre-set temperature and the limit slope of load current can be tuned to accommodate different load conditions and temperatures. The proposed design was fabricated with a 0.18µm CMOS process with a chip area of 0.073mm². Chip measurement results show that the proposed design reduces charging time by 18% over the conventional thermal shutdown structure.

A 45MHz-2.5GHz broadband CMOS up-conversion mixer implemented in a conventional 0.18µm CMOS technology is presented in this letter. The offered mixer employs a bisymmetric class-AB input stage in order to provide a high linearity and match the IF input impedance over a 0.3-20.15MHz frequency range. The up-conversion mixer draws 3mA current from a 1.8V supply voltage, and the core chip dimension of the mixer is 0.05*0.08mm². At the frequency range of 45MHz-2.5GHz, the output third-order intercept point (OIP3) is larger than 9dBm, the LO-RF isolation characteristic of the mixer is less than -60dB, and the maximum conversion gain is 5.21dB. The mixer achieves a minimum noise figure of 8.42dB.

This paper presents a wide rate range receiver including adaptive continuous time linear equalizer (CTLE) and loop-unrolled half rate decision feedback equalizer (DFE). A hybrid filter is adopted to expand the rate range of adaptive CTLE with spectrum balancing technology. The current-integrating summer is introduced to reduce the power of half-rate loop-unrolled DFE. The post-simulation is carried out by 0.18µm CMOS TSMC technology and the results show that the rate range of adaptive CTLE can reach to 6.25-10Gb/s. When the 10 Gb/s PRBS7 signal is transmitted through the 18-inch FR4 backplane with 15.451dB loss at Nyquist frequency, the eye diagram is obviously open and its horizontal opening is about 0.9UI.