Abstract: An amplifier circuit includes a power amplifier biased for saturated mode operation, and a controllable current source to provide supply current to the power amplifier. The controllable current source effects desired amplitude modulation of the output signal from the power amplifier by modulating the supply current it provides responsive to an amplitude information signal.

Abstract: An apparatus for monitoring a power amplifier coupled to a transmission medium includes a detector circuit, coupled to the transmission medium, that generates first and second detector signals corresponding to respective fundamental and harmonic components of a power amplifier output signal produced by the power amplifier. A comparing circuit is coupled to the detector circuit and compares the first and second detector signals. The comparing circuit, responsive to a comparison of the first and second detector signals, may generate a signal that indicates linearity of the power amplifier. In some embodiments, the detector circuit may generate the second detector signal without requiring phase information for the harmonic component. In other embodiments, a control circuit controls linearity of the power amplifier responsive to comparison of the first and second detector signals, for example, by controlling power amplifier bias and/or input signal level based on the comparison.

Abstract: A radio frequency power amplifier circuit provides linear amplitude modulation of a radio frequency output signal while operating in a saturated amplification mode. The power amplifier circuit incorporates a lossy modulator that functions as a variable resistance responsive to an amplitude modulation signal. A supply voltage is coupled to the voltage supply input of the power amplifier circuit through the lossy modulator, such that the supply voltage applied to the power amplifier varies with the amplitude modulation signal. The radio frequency power amplifier circuit modulates the envelope of an RF output signal generated by saturated mode amplification of a constant envelope radio frequency input signal.

Abstract: A Doherty amplifier circuit is provided comprising a digital signal processor for producing separated amplitude and phase modulated waveforms, and a plurality of class E amplifiers in communication with the digital signal processor. Each of the amplifiers has an input for receiving signals corresponding to the waveforms, and outputs linked to a shared load network. In this way, a scheme for efficient amplification of amplitude modulated waveforms is achieved across a wide dynamic range and for a large peak-to-average ratio using only input modulated techniques.

Abstract: A circuit for providing a multiplexed input to an amplifier load matching network. The circuit includes a control device receiving amplitude information and phase information from a primary waveform, a plurality of switching devices in communication with the control device and the amplifier, wherein each of the switching devices has a different “ON” resistance. The control device uses the amplitude information to select an active switching device and to control the device using phase information to create a secondary waveform for input to the load matching network. In this way, an amplitude modulated waveform is amplified at high efficiency, enabling application of either all or part of the phase and/or amplitude modulation at the input of the amplifier.

Abstract: A high-Q precision integrated reversibly trimmable singleband oscillator and tunable multiband oscillator are presented that overcome the problems laser trimming and solid state switches. This is accomplished using micro-electromechanical system (MEMS) technology to integrate an amplifier and its tunable LC network on a common substrate. The LC network can be configured to provide a very narrow bandwidth frequency response which peaks at one or more very specific predetermined frequencies without de-Qing the oscillator.

Abstract: Power amplifiers having reactive networks (such as classes C, C-E, E and F) employ tunable reactive devices in their reactive networks, with the reactive devices respective reactance values capable of being adjusted by means of respective control signals. The tunable reactive devices are made from micro-electromechanical (MEM) devices capable of being integrated with the control circuitry needed to produce the control signals and other amplifier components on a common substrate. The reactive components have high Q values across their adjustment range, enabling the amplifier to produce an output with a low harmonic content over a wide range of input signal frequencies, and a frequency agile, high quality output. The invention can be realized on a number of foundry technologies.

Abstract: A frequency stabilizer circuit in the form of a charge-pump phase-lock loop utilizing a MEMS capacitance device, preferably a tunable MEMS capacitor or a MEMS capacitor bank, which more rapid and with a greater precision determine the phase and frequency of a carrier signal so that it can be extracted, providing an information signal of interest. Such MEMS devices have the added advantage of providing linear capacitance, low insertion losses, higher isolation and high reliability, they run on low power and permit the entire circuit to be fabricated on a common substrate. The use of the MEMS capacitance device reduces unwanted harmonics generated by the circuit's charge pump allowing the filtering requirements to be relaxed or perhaps eliminated.

Abstract: The passive components of a transceiver, such as transmit/receive switches, antennas, inductors, capacitors and resonators, are integrated together on a common substrate to form an integrated passive transceiver section, which, in combination with other components, provides a highly reliable, low-cost, high-performance transceiver. Micro-electromechanical (MEM) device fabrication techniques are used to provide low-loss, high-performance switches and low-loss, high-Q reactive components, and enable the passive transceiver section's high level of integration. The passive components are preferably integrated on a low-cost glass substrate, with transceiver circuits containing active components fabricated on a separate substrate; the separate substrates are interconnected to implement the RF/analog and analog/digital interface portions of a transceiver. Additional MEM switching devices permit multiple, parallel signal paths to be switched in and out of the transceiver circuitry as needed to optimize performance.

Abstract: A high-performance integrable tunable inductor includes a "primary" coil and a "drive" coil placed in close proximity to each other and simultaneously driven with primary and drive currents, respectively. The drive current induces mutual components of inductance in the primary coil which vary with the phase and amplitude relationship between the two currents. These relationships are controlled to precisely establish the impedance of the primary coil, allowing the inductor to be "tuned" to provide a desired inductance or resistance by simply varying the phase and amplitude relationships appropriately. Inductance values tunable over ranges of about 2:1 and Q values of nearly 2000 have been demonstrated. The primary coil can also be made to operate as a relatively large integrated capacitance by setting the phase and amplitude relationships appropriately.

Abstract: A high Q MEMS capacitor that can be continuously tuned with a large tuning ratio or reversibly trimmed using an electrostatic force. The tunable capacitor has a master/slave structure in which a control voltage is applied to the master (control) capacitor to set the capacitance of the slave (signal) capacitor to which an RF signal is applied via a suspended mechanical coupler. The master-slave structure reduces tuning error by reducing the signal capacitor's surface area and increasing its spring constant, and may eliminate the need for discrete blocking inductors by electrically isolating the control and signal capacitors. The trimmable capacitor provides an electrostatic actuator that selectively engages a stopper with teeth on a tunable capacitor structure to fix the trimmed capacitance.

Abstract: A monolithically integrated switched capacitor bank using MEMS technology that is capable of handling GHz signal frequencies in both the RF and millimeter bands while maintaining precise digital selection of capacitor levels over a wide tuning range. Each MEMS switch includes a cantilever arm that is affixed to the substrate and extends over a ground line and a gapped signal line. An electrical contact is formed on the bottom of the cantilever arm positioned above and facing the gap in the signal line. A top electrode atop the cantilever arm forms a control capacitor structure above the ground line. A capacitor structure, preferably a MEMS capacitor suspended above the substrate at approximately the same height as the cantilever arm, is anchored to the substrate and connected in series with a MEMS switch.

Abstract: An integrated, tunable inductance network features a number of fixed inductors fabricated on a common substrate along with a switching network made up of a number of micro-electromechanical (MEM) switches. The switches selectably interconnect the inductors to form an inductance network having a particular inductance value, which can be set with a high degree of precision when the inductors are configured appropriately. The preferred MEM switches introduce a very small amount of resistance, and the inductance network can thus have a high Q. The MEM switches and inductors can be integrated using common processing steps, reducing parasitic capacitance problems associated with wire bonds and prior art switches, increasing reliability, and reducing the space, weight and power requirements of prior art designs.

Abstract: An integrated, variable gain microwave frequency power amplifier comprises a number of individual amplifier stages which contain microwave frequency active devices. Each stage is fed with a common input signal, and the individual stage outputs are connected to respective micro-electromechanical (MEM) switches which, when closed, connect the individual outputs together to form the power amplifier's output. The power amplifier's gain is determined by the number of outputs connected together. The preferred switch provides low insertion loss and excellent electrical isolation, enabling a number of amplifier stages to be efficiently interconnected to provide a wide dynamic range power amplifier. The switches are preferably integrated on a common substrate with the active devices, eliminating the need for wire bonds and reducing parasitic capacitances.