GaN C-Band HPA for Phased-Array Applications
In the UMS GH25-10 GaN MMIC technology a C-band high power amplifier (HPA) has been realized. The current design is primarily intended for use in a space-based SAR system with a center frequency of 5.4 GHz and a sweep bandwidth of 100 MHz. To enable reuse of the amplifier in other radar systems such as weather radar, a large bandwidth is required. A design bandwidth from 5 to 6 GHz has been used. Simulation and measurement data from on-wafer and mounted samples will be shown. Showing more than 50 W output power with 45% efficiency the HPA shows sufficient performance to be used in a module for state-of-the-art active electronically scanned arrays. The measured output power and efficiency are a record for MMIC amplifiers.
20W S-band high power amplifier using stacked FET topology
Power amplifiers based on stacked Field Effect Transistor (FET) stages are often applied in silicon based technologies. The application of stacked FETs in Gallium Arsenide (GaAs) power amplifiers potentially leads to Monolithic Microwave Integrated Circuits (MMIC) devices with increased output power per chip area due to the efficient power combining. Furthermore the increased supply voltage results in lower supply currents. In this paper the design and results of a 20 W S-band High Power Amplifier (HPA) are given. Stability and thermal aspect are addressed and the experimental results show an output power in excess of 20 W with a peak Power Added Efficiency (PAE) of more than 40 %.
An Ultrasensitive Analytical Method Based on Chemiluminescence Sensing Electrochemical Parallel Catalytic Reaction Event
An ultrasensitive electrochemiluminescence (ECL) method on the combination of electrochemical parallel catalytic reaction and chemiluminesence signal sensing was proposed for improving ECL analytical characteristics using vanadate(V) as a representative. Vanadate(V) could be electrochemically reduced to generate vanadate(II) which could be chemically oxidized by potassium periodate to regenerate vanadate(V) and give parallel catalytic wave effect. Then, the reduced product of potassium periodate could react with butyl-rhodamine B to emit a sensitive chemiluminescence signal. The chemiluminescence intensity was correlative with vanadate(V) concentration. The investigation on the electrochemical reaction rate constant (k0) confirmed that the speed of electrochemical reaction was faster than that of the subsequent chemiluminescence reaction. The possibility of the combination of electrochemical parallel catalytic reaction with chemiluminescence signal sensing was proved. The similar ECL behaviors could be observed at zirconia nanowires-Nafion modified electrode. Because of the separation and enrichment effect of the modified electrode on vanadate(V), the selectivity and sensitivity was further improved greatly. Based on these findings, a new concept on the combination of electrochemical parallel catalytic reaction and chemiluminesence signal sensing was proposed and an ultrasensitive ECL method for the determination of vanadate(V) was developed at zirconia nanowires-Nafion modified electrode. Under the optimum experimental conditions, the ECL intensity was linear with the concentration of vanadate(V) in the range of 2.0×10−12 mol/L–2.0×10−10 mol/L. The detection limit was 8.0×10−13 mol/L, which was more than 6 orders of magnitude lower than that observed by electrochemical current transduction for electrochemical parallel catalytic reaction at zirconia nanowires-Nafion modified electrode.