Abstract: Present invention relate to a wideband signal source. The wideband signal source comprises a voltage controlled oscillator (VCO), a first buffer and a programmable frequency extender. The VCO outputs a signal with at least N:1 frequency tuning ratio, with N being an integer or a non-integer number larger than 1. The frequency extender receives the signal via the buffer to generate a final output, which has a wider frequency band than the signal. The buffer isolates the final output from interfering VCO for VCO operation stability. The frequency extender comprises at least a 1/N frequency divider, which matches the N:1 frequency tuning ratio of the signal, such that the final output has a gapless frequency band wider than the VCO output signal.

Abstract: Various embodiments of the invention relate to a high performance analog bandpass filter (BPF) with improved performance in suppressing parasitic passband. The BPF comprises a first loss-pass filter (LPF) coupled to a first RF port, a second LPF coupled to a second RF port, and at least one high-pass module coupled in series between the first LPF and the second LPF for band-pass tuning. A resonant circuit is composed by a shunt capacitor from the LPF, a shunt inductor from the high-pass module and a series inductor from the LPF coupled in between. Such layout empowers the LPFs triple functions: to function as a low-pass filter, to participate in resonant circuit for center frequency tuning of the BPF, and to suppress parasitic resonance. Such a triple-function of the LPFs gives the BPF an improvement in a compact but effective topology.

Abstract: Various embodiments of the invention relate to a Multi-Band Voltage Controlled Oscillator (VCO). The multi-band VCO features a coupled-inductor based resonator. The resonator comprises a primary path and a secondary path inductively coupled to the primary path. The primary path comprises multiple LC tuning stages coupled in series with each stage having an adjustable capacitor and a primary inductor inductively coupled to the secondary path. The secondary path comprises multiple secondary inductors inductively coupled to respective primary inductors in the primary path. Furthermore, the secondary path comprises a plurality of controllable switches which are controlled to switch ON or OFF simultaneously to engage/disengage the inductive coupling between the primary path and the secondary path. Incorporating multiple LC tuning stages lowers voltage swing across each tuning stages, thus minimizing phase noise caused by nonlinearity in the resonator.

Abstract: Present invention relate to a wideband signal source. The wideband signal source comprises a voltage controlled oscillator (VCO), a first buffer and a programmable frequency extender. The VCO outputs a signal with at least N:1 frequency tuning ratio, with N being an integer or a non-integer number larger than 1. The frequency extender receives the signal via the buffer to generate a final output, which has a wider frequency band than the signal. The buffer isolates the final output from interfering VCO for VCO operation stability. The frequency extender comprises at least a 1/N frequency divider, which matches the N:1 frequency tuning ratio of the signal, such that the final output has a gapless frequency band wider than the VCO output signal.

Abstract: The invention discloses a voltage controlled oscillator (VCO) based on hybrid resonator, including a hybrid resonator and a negative resistance circuit, wherein the hybrid resonator includes the first LC series resonance branch, the second LC series resonance branch and the third LC series resonance branch. The first LC series resonance branch and the second LC series resonance branch forms a parallel structure, in which one end of the said parallel structure is grounded while the other end is connected to the third LC series resonance branch, and the other end of the third LC series resonance branch is connected to the negative resistance circuit. The resonance frequency of the first LC series resonance branch is lower than that of the second LC series resonance branch. The invented VCO can effectively improve the phase noise, especially maintain a good phase noise with the increase of the tuning frequency.

Abstract: Various embodiments of the invention relate to a high accuracy phase shift apparatus. The phase shift apparatus comprises a voltage controlled analog phase shifter, a microcontroller unit (MCU) and a digital-to-analog converter (DAC). The MCU generates a digital control signal, which is converted into an analog control signal by the DAC to control the voltage controlled analog phase shifter to achieve desired phase shift angle. The phase shift apparatus may further incorporate a temperature sensor for temperature compensation. The output from the temperature sensor may be used to modify the reference voltage of the DAC, or alternatively be used to modify the digital control signal from the MCU. By incorporation digitalized control and temperature compensation to an analog phase shifter, the disclosed phase shift apparatus achieves high accuracy digitalized control, a flat phase shift over a wide bandwidth, and a stable phase shift over temperature variation.

Abstract: The invention discloses a frequency extender, including a preamplifier to receive a RF input signal and output a pre-amplified RF signal, a series frequency multiplier branch, a series frequency divider branch and a multiplexer. The output port of the preamplifier couples to one input port of the multiplexer. The series frequency multiplier branch and the series divider branch are coupled to receive the pre-amplified RF signal. The output port of each frequency multiplier in the series multiplier branch and/or the output port of each frequency divider in the series divider branch are coupled to the input ports of the multiplexer respectively. The multiplexer couples to receive the pre-amplified RF signal, the frequency-multiplied RF signal and the frequency-divided signal, the multiplexer selects a signal from the received signals and outputs a multiplexer output signal based on the selected signal.

Abstract: This invention relates to analog phase shifters, and more particularly, to analog phase shifters for controlling the phase of an RF signal over a wide range of frequencies with nearly linear phase change. An exemplary phase shifter includes a front end high-low pass filter, a back-end high-low pass filter, and an all-pass filter coupled in series between the two high-low pass filters. At least one of the filters is tunable for controlling the phase of an input signal over a wide range of frequencies. The high-low pass filter comprises low-pass filters as input and output interface for the high-low pass filter to facilitate impedance match for receiving and outputting RF signal.

Abstract: This invention relates to analog phase shifters, and more particularly, to analog phase shifters for controlling the phase of an RF signal over a wide range of frequencies with nearly linear phase change. An exemplary phase shifter includes a front end high-low pass filter, a back-end high-low pass filter, and an all-pass filter coupled in series between the two high-low pass filters. At least one of the filters is tunable for controlling the phase of an input signal over a wide range of frequencies. The high-low pass filter comprises low-pass filters as input and output interface for the high-low pass filter to facilitate impedance match for receiving and outputting RF signal.

Abstract: The disclosure discloses a multiplexer based frequency extender comprising a preamplifier to receive a RF input signal and output a pre-amplified RF signal, at least one frequency multiplier or at least one frequency divider, and a multiplexer. The multiplexer comprises multiple differential pairs, each differential pair comprises a corresponding bias current control circuit that switches ON or OFF a bias current flowing through a corresponding differential pair. The at least one frequency multiplier or the at least one frequency divider receives the pre-amplified RF signal and outputs a frequency-multiplied RF signal or a frequency-divided signal. The multiplexer couples to receive the pre-amplified RF signal, the frequency-multiplied RF signal and/or the frequency-divided signal, the multiplexer selects a signal from the received signals and outputs based on the selected signal a multiplexer output signal.

Abstract: The disclosure discloses a multiplexer based frequency extender comprising a preamplifier to receive a RF input signal and output a pre-amplified RF signal, at least one frequency multiplier or at least one frequency divider, and a multiplexer. The multiplexer comprises multiple differential pairs, each differential pair comprises a corresponding bias current control circuit that switches ON or OFF a bias current flowing through a corresponding differential pair. The at least one frequency multiplier or the at least one frequency divider receives the pre-amplified RF signal and outputs a frequency-multiplied RF signal or a frequency-divided signal. The multiplexer couples to receive the pre-amplified RF signal, the frequency-multiplied RF signal and/or the frequency-divided signal, the multiplexer selects a signal from the received signals and outputs based on the selected signal a multiplexer output signal.

Abstract: The invention discloses a voltage controlled oscillator (VCO) based on hybrid resonator, including a hybrid resonator and a negative resistance circuit, wherein the hybrid resonator includes the first LC series resonance branch, the second LC series resonance branch and the third LC series resonance branch. The first LC series resonance branch and the second LC series resonance branch forms a parallel structure, in which one end of the said parallel structure is grounded while the other end is connected to the third LC series resonance branch, and the other end of the third LC series resonance branch is connected to the negative resistance circuit. The resonance frequency of the first LC series resonance branch is lower than that of the second LC series resonance branch. The invented VCO can effectively improve the phase noise, especially maintain a good phase noise with the increase of the tuning frequency.

Abstract: The invention discloses a frequency extender, including a preamplifier to receive a RF input signal and output a pre-amplified RF signal, a series frequency multiplier branch, a series frequency divider branch and a multiplexer. The output port of the preamplifier couples to one input port of the multiplexer. The series frequency multiplier branch and the series divider branch are coupled to receive the pre-amplified RF signal. The output port of each frequency multiplier in the series multiplier branch and/or the output port of each frequency divider in the series divider branch are coupled to the input ports of the multiplexer respectively. The multiplexer couples to receive the pre-amplified RF signal, the frequency-multiplied RF signal and the frequency-divided signal, the multiplexer selects a signal from the received signals and outputs a multiplexer output signal based on the selected signal.

Abstract: Aspects of this disclosure relate to a first die includes an LC resonant circuit including a first capacitive element, such as a capacitor or a varactor, and an inductive element. The LC resonant circuit is configured to generate a signal having a frequency of oscillation. The first die includes bump pads electrically coupled to both ends of the first capacitive element. A second die can be flip chip mounted on the first die. Bumps can electrically connect a second capacitive element of the second die in parallel with the first capacitive element of the first die. This can increase the Q factor of the LC resonant circuit.

Abstract: Apparatus and methods for multi-mode low noise amplifiers (LNAs) are provided herein. In certain configurations, a radio frequency (RF) system includes a multi-mode LNA including at least a first amplification stage and a second amplification stage electrically connected in a cascade. The RF system further includes a mode control circuit, which receives a mode selection signal and controls the biasing of the first and second amplification stages based on the mode selection signal. The mode control circuit operates the multi-mode LNA in one of a plurality of modes including both a first mode in which the LNA operates with higher gain and better noise figure and a second mode in which the LNA operates with lower gain and higher linearity. Controlling the mode of the multi-mode LNA using the mode selection signal allows the multi-mode LNA to advantageously achieve both the benefits of low noise figure and high linearity.

Abstract: A die is packaged by flip-chip mounting the die with the active side facing a low loss substrate. A ground plane is coupled to the active side of the die by vias through the low loss substrate. The ground plane is positioned to concentrate high frequency electromagnetic fields in the low loss substrate. A tuning height can be adjusted to tune the center frequency of a circuit in the die.

Abstract: Aspects of this disclosure relate to a first die includes an LC resonant circuit including a first capacitive element, such as a capacitor or a varactor, and an inductive element. The LC resonant circuit is configured to generate a signal having a frequency of oscillation. The first die includes bump pads electrically coupled to both ends of the first capacitive element. A second die can be flip chip mounted on the first die. Bumps can electrically connect a second capacitive element of the second die in parallel with the first capacitive element of the first die. This can increase the Q factor of the LC resonant circuit.

Abstract: Apparatus and methods for multi-mode low noise amplifiers (LNAs) are provided herein. In certain configurations, a radio frequency (RF) system includes a multi-mode LNA including at least a first amplification stage and a second amplification stage electrically connected in a cascade. The RF system further includes a mode control circuit, which receives a mode selection signal and controls the biasing of the first and second amplification stages based on the mode selection signal. The mode control circuit operates the multi-mode LNA in one of a plurality of modes including both a first mode in which the LNA operates with higher gain and better noise figure and a second mode in which the LNA operates with lower gain and higher linearity. Controlling the mode of the multi-mode LNA using the mode selection signal allows the multi-mode LNA to advantageously achieve both the benefits of low noise figure and high linearity.

Abstract: This invention features an absorptive tunable bandstop filter with a wide tuning range including first and second branches of all-pass filter networks, an input power divider for splitting the input signal and passing approximately half of the input signal power through each branch of the all-pass filter networks, and an output power combiner for recombining the signal power from each branch of the all-pass filter networks, at least one of the branches of the all-pass filter networks being electrically tunable to provide an approximately 180° phase difference with similar amplitudes of the split signal power to be recombined at the output power combiner for rejecting but substantially absorbing selected frequencies.

Abstract: An injection locked pulsed oscillator includes a voltage controlled oscillator (VCO) responsive to an injection signal. The injection locked pulsed oscillator includes at least one enable circuit responsive to a first enable signal to enable output pulses from the VCO. The injection locked pulsed oscillator also includes timing circuit responsive to a pulse repetition frequency signal and is configured to provide the injection signal to phase lock the VCO and provide the first enable signal delayed from the injection signal to shape a width of the output pulses from the VCO.