A 2.5-GS/s 62dB THD SiGe Track-and-Hold Amplifier with feedthrough cancellation technique
In this paper a Track-and-Hold Amplifier (THA), designed in a low cost 0.35μm SiGe 60GHz technology is presented. Thanks to the joint action of a novel input buffer and a suppression feedthrough architecture, it is able to guarantee 62dB Total Harmonic Distortion(THD) up to a frequency of 2.2GHz with 0.9Vp-p differential input at a sampling rate (Fs) of 2.5GS/s. The THA core draws about 145mA from 3.5V supply.
A very wide-band 14 bit, 1 GS/s track-and-hold amplifier
The track-and-hold amplifier (THA) is a key sub-circuit in a data acquisition and conversion system. The input buffer of the THA employs an open-loop linearization technique to reduce distortion and increase bandwidth. The hold mode feedthrough is reduced by the replica switch technique. The parasitic capacitance compensation technique is employed to further improve the signal bandwidth of the THA. Simulation results indicate that the parasitic capacitance compensation technique improves the bandwidth by approximately a factor of 5. The THA circuit was designed using a 60 GHz f/sub T/ InGaP-GaAs HBT process. Simulation results are 83 dB spurious-free dynamic range (SFDR) at 100 MHz sampling frequency, 65 dB SFDR at 1 GHz sampling frequency, and 60 dB SFDR at 2 GHz sampling frequency under all Nyquist conditions.
Microwave source with enhanced radiation power based on orbitron MASERs
We have proposed the design of high power microwave source in a vacuum tube based on the theory of negative mass instability. The proposed source does not operate based on a slow-wave structure but instead makes use of accelerated charged particles. In our structure, an electron emitter injects the charged particles into to the cavity. Emitted particles move around the anode, which leads to electron acceleration and emission of electromagnetic waves with a specific frequency. In this paper, we have enhanced the output power and frequency of microwave source by variation of particles initial energy and the number of anodes incorporating their specific arrangement and applied voltages. Working at room temperature, compactness, wide bandwidth, and tunability of output frequency are among the advantages of the proposed source.