Abstract: A multi-stage radio frequency power amplifier (RFPA) includes an output stage SMPA and a driver stage SMPA. As the multi-stage RFPA operates, the magnitude of an RF switch drive signal generated by the driver stage SMPA is dynamically minimized based on I-V characteristic curves of the output stage SMPA's power transistor and the output stage SMPA's dynamically changing load line. By constraining the magnitude of the RF switch drive signal as the multi-stage RFPA operates, VGS feedthrough of the RF switch drive signal is minimized, to the extent possible. Amplitude distortion and phase distortion in the RF output that might occur due to unconstrained VGS feedthrough, particularly at low output RF power levels, are therefore avoided. Operating all stages of the multi-stage RFPA in switch mode also results in high energy efficiency and an output RF spectrum with very low wideband noise (WBN).

Abstract: A switch-mode RFPA driver includes first and second field-effect transistors (FETs) arranged in a totem-pole-like configuration. The switch-mode RFPA driver operates to generate a switch-mode RFPA drive signal having a generally square-wave-like waveform from an input RF signal having a generally sinusoidal-like waveform. To maximize high-frequency operation and avoid distorting the switch-mode RFPA drive signal, the switch-mode RFPA driver is designed so that its output can be connected directly to the input of the switch-mode RFPA to be driven, i.e., without using or requiring the use of an AC coupling capacitor. The first and second FETs of the switch-mode RFPA driver are designed and configured to limit and control the upper and lower magnitude levels of the switch-mode RFPA drive signal to levels suitable for switching the switch-mode RFPA directly, obviating any need for DC biasing at the input of the switch-mode RFPA.

Abstract: A multi-stage radio frequency power amplifier (RFPA) includes an output stage SMPA and a driver stage SMPA. As the multi-stage RFPA operates, the magnitude of an RF switch drive signal generated by the driver stage SMPA is dynamically minimized based on I-V characteristic curves of the output stage SMPA's power transistor and the output stage SMPA's dynamically changing load line. By constraining the magnitude of the RF switch drive signal as the multi-stage RFPA operates, VGS feedthrough of the RF switch drive signal is minimized, to the extent possible. Amplitude distortion and phase distortion in the RF output that might occur due to unconstrained VGS feedthrough, particularly at low output RF power levels, are therefore avoided. Operating all stages of the multi-stage RFPA in switch mode also results in high energy efficiency and an output RF spectrum with very low wideband noise (WBN).

Abstract: A driver interface for a switch-based circuit includes an AC coupling capacitor, a first diode or a first series of diodes, and a second diode or a second series of diodes connected in series with the first diode or first series of diodes but with an opposing polarity. The AC coupling capacitor removes a DC voltage from an input bi-level drive signal that does not have the appropriate high and low drive levels needed to switch a FET in the switch-based circuit between fully ON and fully OFF states. The first diode or first series of diodes and the second diode or second series of diodes clamp the resulting AC-coupled drive signal to produce an output bi-level drive signal having the high and low drive levels needed to switch the FET between fully ON and fully OFF states. The driver interface maintains the high and low drive levels of the output bi-level drive signal irrespective of any changes made to the duty cycle or pulse density of the input bi-level drive signal.

Abstract: A driver interface for a switch-based circuit includes an AC coupling capacitor, a first diode or a first series of diodes, and a second diode or a second series of diodes connected in series with the first diode or first series of diodes but with an opposing polarity. The AC coupling capacitor removes a DC voltage from an input bi-level drive signal that does not have the appropriate high and low drive levels needed to switch a FET in the switch-based circuit between fully ON and fully OFF states. The first diode or first series of diodes and the second diode or second series of diodes clamp the resulting AC-coupled drive signal to produce an output bi-level drive signal having the high and low drive levels needed to switch the FET between fully ON and fully OFF states. The driver interface maintains the high and low drive levels of the output bi-level drive signal irrespective of any changes made to the duty cycle or pulse density of the input bi-level drive signal.

Abstract: A switch-mode RFPA driver includes first and second field-effect transistors (FETs) arranged in a totem-pole-like configuration. The switch-mode RFPA driver operates to generate a switch-mode RFPA drive signal having a generally square-wave-like waveform from an input RF signal having a generally sinusoidal-like waveform. According to one embodiment of the invention, to maximize high-frequency operation and avoid distorting the switch-mode RFPA drive signal, the switch-mode RFPA driver is designed so that its output can be connected directly to the input of the switch-mode RFPA to be driven, i.e., without using or requiring the use of an AC coupling capacitor. The first and second FETs of the switch-mode RFPA driver are designed and configured to limit and control the upper and lower magnitude levels of the switch-mode RFPA drive signal to levels suitable for switching the switch-mode RFPA directly, obviating any need for DC biasing at the input of the switch-mode RFPA.

Abstract: A high-power solid-state RFPA includes an output stage having a power transistor and a current enhanced driver that drives the output stage. The current enhanced driver includes an inductor and first and second transistors arranged in totem-pole-like configuration. When the first transistor is turned on and the second transistor is turned off, the inductor supplies a first charging current to the output stage, to assist in charging the input gate-source capacitor (Cgs) of the power transistor in the output stage. The first transistor further provides a second charging current that supplements the first charging current, thereby enhancing charging of the gate-source capacitor Cgs. Conversely, when the first transistor of the driver is turned off and the second transistor is turned on, the second transistor provides a discharge path through which the gate-source capacitor Cgs can discharge.

Abstract: A driver interface for a switch-based circuit includes an AC coupling capacitor, a first diode or a first series of diodes, and a second diode or a second series of diodes connected in series with the first diode or first series of diodes but with an opposing polarity. The AC coupling capacitor removes a DC voltage from an input bi-level drive signal that does not have the appropriate high and low drive levels needed to switch a FET in the switch-based circuit between fully ON and fully OFF states. The first diode or first series of diodes and the second diode or second series of diodes clamp the resulting AC-coupled drive signal to produce an output bi-level drive signal having the high and low drive levels needed to switch the FET between fully ON and fully OFF states. The driver interface maintains the high and low drive levels of the output bi-level drive signal irrespective of any changes made to the duty cycle or pulse density of the input bi-level drive signal.

Abstract: A high-power, high-frequency radio frequency power amplifier includes an output stage and a single-phase driver. The output stage is arranged in a Class-D amplifier configuration and includes a first depletion mode field effect transistor (FET), a second depletion mode FET, and a bootstrap path that couples the output of the output stage to the gate of the second FET. The first and second depletion mode FETs are switched out-of-phase and between fully-ON and fully-OFF states, under the direction of the single-phase driver. The single-phase driver directly controls the ON/OFF state of the first depletion mode FET and provides a discharge path through which the input gate capacitor of the second depletion mode FET in the output stage can discharge to turn OFF the second depletion mode FET. The bootstrap path provides a current path through which the input gate capacitor of the second depletion mode FET can charge to turn the second depletion mode FET ON.

Abstract: A universal transmit-receive (UTR) module for phased array systems comprises an antenna element shared for both transmitting and receiving; a transmit path that includes a transmit-path phase shifter, a driver, a switch-mode power amplifier (SMPA) that is configured to be driven by the driver, and a dynamic power supply (DPS) that generates and supplies a DPS voltage to the power supply port of the SMPA; and a receive path that includes a TX/RX switch that determines whether the receive path is electrically connected to or electrically isolated from the antenna element, a bandpass filter (BPF) that aligns with the intended receive frequency and serves to suppress reflected transmit signals and reverse signals, an adjustable-gain low-noise amplifier (LNA), and a receive-path phase shifter. The UTR module is specially designed for operation in phased array systems.

Abstract: A high-speed, high-voltage gallium nitride based (GaN-based) operational amplifier (op amp) is disclosed. The combined high-speed, high-voltage capability allows the GaN-based op amp to serve as a dynamic power supply (DPS) for a radio frequency power amplifier (RFPA). When serving as a DPS for an RFPA, the GaN-based op amp is capable of supplying ampere-scale currents that accurately track rapidly-varying envelopes of non-constant envelope RF signals, thereby allowing the RFPA to convert high-bandwidth non-constant envelope RF signals to high RF output powers with high signal envelope accuracy.

Abstract: A high-power, high-frequency radio frequency power amplifier includes an output stage and a single-phase driver. The output stage is arranged in a Class-D amplifier configuration and includes a first depletion mode field effect transistor (FET), a second depletion mode FET, and a bootstrap path that couples the output of the output stage to the gate of the second FET. The first and second depletion mode FETs are switched out-of-phase and between fully-ON and fully-OFF states, under the direction of the single-phase driver. The single-phase driver directly controls the ON/OFF state of the first depletion mode FET and provides a discharge path through which the input gate capacitor of the second depletion mode FET in the output stage can discharge to turn OFF the second depletion mode FET. The bootstrap path provides a current path through which the input gate capacitor of the second depletion mode FET can charge to turn the second depletion mode FET ON.

Abstract: A high-power solid-state RFPA includes an output stage having a power transistor and a current enhanced driver that drives the output stage. The current enhanced driver includes an inductor and first and second transistors arranged in totem-pole-like configuration. When the first transistor is turned on and the second transistor is turned off, the inductor supplies a first charging current to the output stage, to assist in charging the input gate-source capacitor (Cgs) of the power transistor in the output stage. The first transistor further provides a second charging current that supplements the first charging current, thereby enhancing charging of the gate-source capacitor Cgs. Conversely, when the first transistor of the driver is turned off and the second transistor is turned on, the second transistor provides a discharge path through which the gate-source capacitor Cgs can discharge.

Abstract: A phase-stiff radio frequency power amplifier (RFPA) is disclosed. The high phase-stiffness property of the RFPA obviates the need for a circulator or other isolation device in applications where the RFPA is used to implement the high-power amplifier in a transmit-receive module (TRM) configured for use in a phased array. The phase-stiff RFPA is designed to operate in switch-mode, resulting in high energy efficiency. Together, the high energy efficiency and high phase-stiffness attributes of the RFPA afford the ability to construct a phased array having a SWaP (Size, Weight and Power) performance that far surpasses that which can be possibly achieved in a phased array constructed from conventional TRMs.

Abstract: A switch-mode RFPA driver includes first and second field-effect transistors (FETs) arranged in a totem-pole-like configuration. The switch-mode RFPA driver operates to generate a switch-mode RFPA drive signal having a generally square-wave-like waveform from an input RF signal having a generally sinusoidal-like waveform. To maximize high-frequency operation and avoid distorting the switch-mode RFPA drive signal, the switch-mode RFPA driver is designed so that its output can be connected directly to the input of the switch-mode RFPA to be driven, i.e., without using or requiring the use of an AC coupling capacitor. The first and second FETs of the switch-mode RFPA driver are designed and configured to limit and control the upper and lower magnitude levels of the switch-mode RFPA drive signal to levels suitable for switching the switch-mode RFPA directly, obviating any need for DC biasing at the input of the switch-mode RFPA.

Abstract: Radio frequency (RF) transmitters and methods of their operation are disclosed. An exemplary RF transmitter includes an RF power amplifier (RFPA), a dynamic power supply (DPS), and a baseband processing unit. The baseband processing unit generates an amplitude modulation (AM) signal that the DPS follows to generate a DPS voltage VDD(t). The DPS voltage VDD(t) serves as a power supply for an output stage of the RFPA. Under most operating conditions the output stage is configured to operate in a compressed mode (C-mode), but is reconfigured to operate in a product mode (or “P-mode) during times low-magnitude events in the AM signal are conveyed to the DPS and become present in the DPS voltage VDD(t) produced by the DPS. Operating the output stage in P-mode overcomes the inability of C-mode operation to reproduce low-magnitude events contained in the AM signal at the RF output of the RFPA.

Abstract: A switch-mode RFPA driver includes first and second field-effect transistors (FETs) arranged in a totem-pole-like configuration. The switch-mode RFPA driver operates to generate a switch-mode RFPA drive signal having a generally square-wave-like waveform from an input RF signal having a generally sinusoidal-like waveform. To maximize high-frequency operation and avoid distorting the switch-mode RFPA drive signal, the switch-mode RFPA driver is designed so that its output can be connected directly to the input of the switch-mode RFPA to be driven, i.e., without using or requiring the use of an AC coupling capacitor. The first and second FETs of the switch-mode RFPA driver are designed and configured to limit and control the upper and lower magnitude levels of the switch-mode RFPA drive signal to levels suitable for switching the switch-mode RFPA directly, obviating any need for DC biasing at the input of the switch-mode RFPA.

Abstract: Radio frequency (RF) transmitters and methods of their operation are disclosed. An exemplary RF transmitter includes an RF power amplifier (RFPA), a dynamic power supply (DPS), and a baseband processing unit. The baseband processing unit generates an amplitude modulation (AM) signal that the DPS follows to generate a DPS voltage VDD(t). The DPS voltage VDD(t) serves as a power supply for an output stage of the RFPA. Under most operating conditions the output stage is configured to operate in a compressed mode (C-mode), but is reconfigured to operate in a product mode (or “P-mode) during times low-magnitude events in the AM signal are conveyed to the DPS and become present in the DPS voltage VDD(t) produced by the DPS. Operating the output stage in P-mode overcomes the inability of C-mode operation to reproduce low-magnitude events contained in the AM signal at the RF output of the RFPA.

Abstract: A switch-mode RFPA driver includes first and second field-effect transistors (FETs) arranged in a totem-pole-like configuration. The switch-mode RFPA driver operates to generate a switch-mode RFPA drive signal having a generally square-wave-like waveform from an input RF signal having a generally sinusoidal-like waveform. According to one embodiment of the invention, to maximize high-frequency operation and avoid distorting the switch-mode RFPA drive signal, the switch-mode RFPA driver is designed so that its output can be connected directly to the input of the switch-mode RFPA to be driven, i.e., without using or requiring the use of an AC coupling capacitor. The first and second FETs of the switch-mode RFPA driver are designed and configured to limit and control the upper and lower magnitude levels of the switch-mode RFPA drive signal to levels suitable for switching the switch-mode RFPA directly, obviating any need for DC biasing at the input of the switch-mode RFPA.

Abstract: A switch-mode RFPA driver includes first and second field-effect transistors (FETs) arranged in a totem-pole-like configuration. The switch-mode RFPA driver operates to generate a switch-mode RFPA drive signal having a generally square-wave-like waveform from an input RF signal having a generally sinusoidal-like waveform. According to one embodiment of the invention, to maximize high-frequency operation and avoid distorting the switch-mode RFPA drive signal, the switch-mode RFPA driver is designed so that its output can be connected directly to the input of the switch-mode RFPA to be driven, i.e., without using or requiring the use of an AC coupling capacitor. The first and second FETs of the switch-mode RFPA driver are designed and configured to limit and control the upper and lower magnitude levels of the switch-mode RFPA drive signal to levels suitable for switching the switch-mode RFPA directly, obviating any need for DC biasing at the input of the switch-mode RFPA.