Abstract: Provided are high quality metal-nitride, such as aluminum nitride (AlN), films for heat dissipation and heat spreading applications, methods of preparing the same, and deposition of high thermal conductivity heat spreading layers for use in RF devices such as power amplifiers, high electron mobility transistors, etc. Aspects of the inventive concept can be used to enable heterogeneously integrated compound semiconductor on silicon devices or can be used in in non-RF applications as the power densities of these highly scaled microelectronic devices continues to increase.

Abstract: Disclosed is a time delay generator 200 apparatus and method. The apparatus includes a time delay gate 212, a mixer 216 (a Gilbert cell circuit), and a current digital to analog converter 206. The mixer 216, comprised of first and second transistor differential pairs 218 and 220, receives an analog input signal 202 without a delay as well as a delayed input signal 210 produced by the time gate delay. The digital to analog converter regulates the relative current flow between a first control signal 232 and a second control signal 238, effectively altering the mixing of the undelayed input signal 208 and the delayed input signal 210 to generate a delayed output signal 214 with a time or phase delay substantially equal to the temporal delay represented by the digital signal input 204. The time delay generator exhibits reduced phase noise and a linear time delay response.

Abstract: Disclosed is a time delay generator 200 apparatus and method. The apparatus includes a time delay gate 212, a mixer 216 (a Gilbert cell circuit), and a current digital to analog converter 206. The mixer 216, comprised of first and second transistor differential pairs 218 and 220, receives an analog input signal 202 without a delay as well as a delayed input signal 210 produced by the time gate delay. The digital to analog converter regulates the relative current flow between a first control signal 232 and a second control signal 238, effectively altering the mixing of the undelayed input signal 208 and the delayed input signal 210 to generate a delayed output signal 214 with a time or phase delay substantially equal to the temporal delay represented by the digital signal input 204. The time delay generator exhibits reduced phase noise and a linear time delay response.

Abstract: Disclosed is a time delay generator 200 apparatus and method. The apparatus includes a time delay gate 212, a mixer 216 (a Gilbert cell circuit), and a current digital to analog converter 206. The mixer 216, comprised of first and second transistor differential pairs 218 and 220, receives an analog input signal 202 without a delay as well as a delayed input signal 210 produced by the time gate delay. The digital to analog converter regulates the relative current flow between a first control signal 232 and a second control signal 238, effectively altering the mixing of the undelayed input signal 208 and the delayed input signal 210 to generate a delayed output signal 214 with a time or phase delay substantially equal to the temporal delay represented by the digital signal input 204. The time delay generator exhibits reduced phase noise and a linear time delay response.

Abstract: A method of detecting a boundary of fluid flowing through a pipe, the method comprising receiving a time-varying signal corresponding to changes in content flowing through the pipe analysing said signal in the time domain, said analysing including processing said signal to produce a processed signal, searching said processed signal for a predetermined feature so as to identify a location of said boundary if said predetermined feature is found.

Abstract: The present invention provides a method and apparatus for transmission of optical communications. The present invention provides an optical transmitter which includes a control circuit to enhance the stability of output power levels, a modulator circuit with precise impedance matching for high frequency performance, and an optical coupling mechanism that relaxes the alignment tolerances between the laser and the fiber and decreases the sensitivity of the gain medium to feedback from devices coupled to the fiber. These features allow the transmitter to deliver an optical output beam which can be modulated over a wide range of frequencies, duty cycles and amplitudes with very precise definition of the rising and falling edges of the waveform. In combination these features result in an optical transmitter that may be fabricated with relatively low cost and a reduced form factor when compared with prior art optical transmitters.

Abstract: A heterojunction bipolar transistor is provided with a graded band gap layer between a base and subcollector region. The graded band gap layer minimizes the surface leakage current path between the base and subcollector.

Abstract: Described embodiments provide a method and apparatus for transmission of optical communications. An embodiment provides an optical transmitter which includes a control circuit to enhance the stability of output power levels, a modulator circuit with precise impedance matching for high frequency performance, and an optical coupling mechanism that relaxes the alignment tolerances between the laser and the fiber and decreases the sensitivity of the gain medium to feedback from devices coupled to the fiber. These features allow the transmitter to deliver an optical output beam which can be modulated over a wide range of frequencies, duty cycles and amplitudes with very precise definition of the rising and falling edges of the waveform. In combination these features result in an optical transmitter that may be fabricated with relatively low cost and a reduced form factor when compared with prior art optical transmitters.

Abstract: A microwave power amplifier is comprised of a plurality of series connected amplifier stages. Each stage is provided with a local negative feedback. The addition of the local voltage feedback distribution networks provide correct voltage distribution and equal current distribution for all transistors, such that the peak-to-peak voltage and current swings of each transistor can be set simultaneously to the values required for efficient amplifier operation. The method applies to both FETs and bipolar transistors. The series connected microwave power amplifier is thus characterized as a stack with local voltage feedback networks which provide an equal distribution of voltage across the transistors in the stack. The amplifier stages can be biased and tuned to collectively operate either as a class A or B amplifier.

Abstract: A high bandwidth RF sampler using equivalent time sampling comprising an RF coplanar waveguide integrated with sampling diodes on a gallium arsenide substrate. A monolithic, integrated coplanar strip nonlinear transmission line is integrated on the same substrate to receive sample pulses. These pulses are reshaped by the nonlinear transmission line to have a very fast edge. This edge is differentiated by a shunt inductance of a short circuit termination of a slot line portion of the RF signal coplanar waveguide. The resulting delta function sample pulses cause the sample diodes and integrated capacitors to develop an intermediate output frequency which is a replica of the RF signal at a lower frequency and no voltage conversion loss. RF signals of up to 300 Ghz can be sampled using this circuit.

Abstract: A high bandwidth RF sampler using equivalent time sampling comprising an RF coplanar waveguide integrated with sampling diodes on a gallium arsenide substrate. A monolithic, integrated nonlinear transmission line is integrated on the same substrate to receive sample pulses. These pulses are reshaped by the nonlinear transmission line to have a very fast edge. This edge is differentiated by a shunt inductance of a short circuit termination of a slot line portion of the RF signal coplanar waveguide. The resulting delta function sample pulses cause the sample diodes and integrated capacitors to develop an intermediate output frequency which is a replica of the RF signal at a lower frequency and no voltage conversion loss. RF signals of up to 300 Ghz can be sampled using this circuit.