Large instantaneous bandwidth radio frequency front-end for wireless systems
The disclosed principles provide for an RF front-end design capable of up-converting, down-converting, and conditioning broadband signals for wireless transmission with an instantaneous bandwidth of up to 3.5 GHz within the frequency range of 2-12 GHz. In addition, embodiments of the disclosed principles provide flexibility that enables RF front-ends designed as disclosed herein to be applied to many different applications including covert communications, drone communications, high data rate communications, signals intelligence, direction finding, multi-function apertures, radars and emulators, and electronic warfare. Embodiments and their related advantages and improvements of RF front-ends designed in accordance with the disclosed principles are discussed herein.
1 . A radio frequency (RF) front-end, comprising:
a receiver having a first coding mixer configured to mix a coding input signal and a signal from a first synthesizer comprising a first center frequency of a RF input signal to generate a first code injected signal; and
a transmitter having a second coding mixer configured to mix the coding input signal and a signal from a second synthesizer comprising a second center frequency of a RF output signal to generate a second code injected signal.
2 . The RF front-end of claim 1 , wherein the first or second coding mixer is configured to be disabled if a corresponding coding input signal is not present, and wherein when the first or second coding mixer is disabled, output from the first or second synthesizer bypasses the corresponding first or second coding mixer.
3 . The RF front-end of claim 2 , wherein the first or second coding mixer is disabled using a DC bias voltage, wherein phase shift of the output from the corresponding first or second synthesizer is 0° for a positive DC bias voltage and 180° for a negative DC bias voltage.
4 . The RF front-end of claim 1 , wherein the coding input signal provides a spreading sequence signal generated by a digital signal processing system.
5 . The RF front-end of claim 4 , wherein the first or second coding mixer mixes a corresponding coding input signal and the output from the corresponding first or second synthesizer to provide pseudo noise coding on the first and second code injected signals.
6 . The RF front-end of claim 1 , wherein the receiver further comprises a low-noise amplifier configured to receive the RF input signal, and to provide an amplified analog RF input signal to a demodulator.
7 . The RF front-end of claim 1 , wherein the first center frequency and the second center frequency are separated by at least 1 GHz.
8 . The RF front-end of claim 1 , wherein the RF input signal received comprises an instantaneous bandwidth no less than 1 GHz.
9 . The RF front-end of claim 8 , wherein the RF output signal transmitted comprises an instantaneous bandwidth, no less than 1 GHz, that does not overlap the instantaneous bandwidth of the RF input signal received.
10 . The RF front-end of claim 1 , wherein the receiver further comprises:
an I-channel mixer configured to down-convert an I-channel component of the RF input signal; and
a Q-channel mixer configured to down-convert a Q-channel component of the RF input signal.
11 . The RF front-end of claim 10 , wherein the receiver further comprises:
an I-channel filter coupled between the I-channel mixer and a first receiver output, and configured to remove harmonics from the down-converted I-channel component; and
a Q-channel filter coupled between the Q-channel mixer and a second receiver output, and configured to remove harmonics from the down-converted Q-channel component.
12 . The RF front-end of claim 11 , wherein the transmitter further comprises:
the I-channel filter coupled between a first transmitter input and the I-channel mixer, and
configured to remove harmonics from the I-channel component from a digital-to-analog converter (DAC); and
the Q-channel filter coupled between a second transmitter input and the Q-channel mixer, and configured to remove harmonics from the Q-channel component from the DAC.
13 . The RF front-end of claim 1 , wherein the transmitter further comprises:
an I-channel mixer configured to up-convert an I-channel component for the RF output signal; and
a Q-channel mixer configured to up-convert a Q-channel component for the RF output signal.
14 . The RF front-end of claim 1 , wherein the transmitter further comprises:
a pre-amplifier receiving the RF output signal from a power combiner; and
a power amplifier receiving the RF output signal from the pre-amplifier and providing the RF output signal to the RF output.
15 . The RF front-end of claim 1 , wherein one or both of the receiver and the transmitter is semi-symmetric.
16 . The RF front-end of claim 1 , wherein the RF input or the RF output is coupled to a corresponding transmit/receive switch, which is coupled to an antenna.
17 . A radio frequency (RF) front-end, comprising:
a receiver having:
an RF input configured to receive an analog RF input signal via an antenna;
a demodulator comprising:
a power divider configured to divide the RF input signal into an I-channel component and a Q-channel component,
a first I-channel mixer configured to down-convert the I-channel component of the RF input signal,
a first Q-channel mixer configured to down-convert the Q-channel component of the RF input signal, and
a first phase quadrature device providing phase separation between the down-converted I and Q channel components via the first I-channel mixer and the first Q-channel mixer, respectively;
a first coding mixer configured to mix a first coding input signal and a signal from a first synthesizer comprising a first center frequency of the RF input signal to generate a first code injected signal;
a first local oscillator gain amplifier driving the first phase quadrature device based on the first code injected signal or the signal from the first synthesizer;
a first receiver output providing the down-converted I-channel component to an I-channel of an analog-to-digital converter (ADC);
a second receiver output providing the down-converted Q-channel component to a Q-channel of the ADC; and
a transmitter having:
a first transmitter input receiving the I-channel component for an analog RF output signal from an I-channel of a digital-to-analog converter (DAC);
a second transmitter input receiving the Q-channel component for the analog RF output signal from a Q-channel of the DAC;
a modulator comprising:
a second I-channel mixer configured to up-convert the I-channel component for the RF output signal,
a second Q-channel mixer configured to up-convert the Q-channel component for the RF output signal,
a second phase quadrature device providing phase separation between the up-converted I and Q channel components via the second I-channel mixer and the second Q-channel mixer, respectively;
a power combiner configured to combine the up-converted I-channel and Q-channel components into the analog RF output signal;
a second coding mixer configured to mix a second coding input signal and a signal from a second synthesizer comprising a second center frequency of the RF output signal to generate a second code injected signal;
a second local oscillator gain amplifier driving the second phase quadrature device based on the second code injected signal or the signal from the second synthesizer; and
an RF output configured to transmit the analog RF output signal via the antenna.
18 . The RF front-end of claim 17 , wherein the first or second coding mixer is configured to be disabled if the corresponding first or second coding input signal is not present, and wherein when the first or second coding mixer is disabled, output from the first or second synthesizer bypasses the corresponding first or second coding mixer.
19 . The RF front-end of claim 17 , wherein the first or second coding input signal provides a spreading sequence signal generated by a digital signal processing system.
20 . The RF front-end of claim 19 , wherein the first or second coding mixer mixes the corresponding coding input signal and the output from the corresponding the first or second synthesizer to provide pseudo noise coding on the corresponding first or second code injected signal provided to the corresponding first or second local oscillator.