Abstract: A solid state RADAR antenna system is provided comprising at least one antenna configured to transmit a plurality of antenna beams. Each antenna beam is decoupled from each of the other plurality of antenna beams for transmitting in a blind range of a different antenna beam. Accordingly, in an implementation, the second antenna beam is transmitted so as to scan a first blind range associated with the first antenna beam. Decoupling antenna beams can be achieved using one or more of physical decoupling using different antennas, frequency decoupling using different bands and/or frequency multiplexing, or orthogonal polarization.

Abstract: A RADAR antenna system and method are provided. In an implementation, the system includes a base and first and second antennas configured to transmit independent first and second antenna beams, respectively. The first and second antennas are each coupled to the base so as to provide a common rotational axis for the first and second antennas. An antenna position controller is configured to independently control first and second transmission positions associated with the first and second antennas, respectively. Two different antenna technologies can be used, for example one for providing communications capability and the other for providing tracking capability. Other implementations include four or more antennas configured to transmit beams at similar or different frequencies. Improvements in scan rate proportional to the number of antennas are achieved compared to that achievable with a single beam, without an increase in the rotation rate of the antenna system.

Abstract: Disclosed herein is a system and method for determining a thickness of ice on Radio Frequency (RF) systems The system includes a sensor unit for use in determining the thickness of ice on a surface of a RADAR system having a RADAR antenna, the sensor unit including a sensor unit antenna tunable to a harmonic of a RADAR antenna signal, the harmonic having a frequency within an ice absorption band, wherein the sensor unit antenna emits the harmonic at a first signal strength; and, a sensor unit receiver communicatively coupled to the sensor unit antenna and configured to detect a second signal strength of the harmonic received by the sensor unit antenna.

Abstract: A filter, apparatus, system and method are provided for implementing a band select filter, for example a frequency agile band select filter. In an implementation, the filter includes two separate signal generators configured to provide different local oscillator signals to an input mixer and to an output mixer, resulting in the filter output frequency being different from the filter input frequency. This is in contrast to known approaches which use the same signal generator to drive both input and output mixers. The filter may include two bandpass filters, three mixers, and three signal generators, each signal generator uniquely associated with one of the mixers, and configured to provide bandwidth control. A system of filters may include a set of bandpass filters, a plurality of sets of mixers, and a plurality of sets of signal generators, each set of signal generators being associated with a different set of mixers.

Abstract: A transposed delay line oscillator including a mode selection filter and a transposed delay line is provided. An output of the transposed delay line is coupled to an input of the mode selection filter to establish an oscillator loop. Based on the transposed delay line output, the mode selection filter generates a mode selection signal including an isolated oscillatory mode, in a Radio Frequency (RF) band. The transposed delay line receives the mode selection signal for transposition to an intermediate frequency of an intermediate frequency (IF) delay line. The IF delay line includes a delay filter and a phase noise suppression loop configured to suppress de-correlated transposition phase noise resulting from a delay of the delay filter. Suppression of phase noise in the IF delay line enables cancellation of transposition phase noise when transposing the IF delay line output to the RF band.

Abstract: A transposed delay line oscillator including a mode selection filter and a transposed delay line is provided. An output of the transposed delay line is coupled to an input of the mode selection filter to establish an oscillator loop. Based on the transposed delay line output, the mode selection filter generates a mode selection signal including an isolated oscillatory mode, in a Radio Frequency (RF) band. The transposed delay line receives the mode selection signal for transposition to an intermediate frequency of an intermediate frequency (IF) delay line. The IF delay line includes a delay filter and a phase noise suppression loop configured to suppress de-correlated transposition phase noise resulting from a delay of the delay filter. Suppression of phase noise in the IF delay line enables cancellation of transposition phase noise when transposing the IF delay line output to the RF band.

Abstract: A transposed delay line oscillator including a mode selection filter and a transposed delay line is provided. An output of the transposed delay line is coupled to an input of the mode selection filter to establish an oscillator loop. Based on the transposed delay line output, the mode selection filter generates a mode selection signal including an isolated oscillatory mode, in a Radio Frequency (RF) band. The transposed delay line receives the mode selection signal for transposition to an intermediate frequency of an intermediate frequency (IF) delay line. The IF delay line includes a delay filter and a phase noise suppression loop configured to suppress de-correlated transposition phase noise resulting from a delay of the delay filter. Suppression of phase noise in the IF delay line enables cancellation of transposition phase noise when transposing the IF delay line output to the RF band.

Abstract: An optoelectronic oscillator (OEO) including a drift compensation circuit is provided. The OEO includes a set of optical domain components communicatively coupled with a set of RF domain components. The RF domain components include a mode selection filter, a phase locked loop (PLL) and a drift compensation circuit communicatively coupled between the mode selection filter and the PLL. The mode selection filter provides a mode selection result to the drift compensation circuit. The drift compensation circuit phase modulates the mode selection result in a vector based coordinate system to maintain a drift compensated mode selection result within a locking bandwidth of the PLL, and to minimize phase shifting from accumulating phase drift. The PLL detects a phase difference between the drift compensated mode selection result and a reference signal, for use in maintaining the PLL in a phase lock with the reference signal, in particular over wide operational temperature ranges.

Abstract: A transposed delay line oscillator including a mode selection filter and a transposed delay line is provided. An output of the transposed delay line is coupled to an input of the mode selection filter to establish an oscillator loop. Based on the transposed delay line output, the mode selection filter generates a mode selection signal including an isolated oscillatory mode, in a Radio Frequency (RF) band. The transposed delay line receives the mode selection signal for transposition to an intermediate frequency of an intermediate frequency (IF) delay line. The IF delay line includes a delay filter and a phase noise suppression loop configured to suppress de-correlated transposition phase noise resulting from a delay of the delay filter. Suppression of phase noise in the IF delay line enables cancellation of transposition phase noise when transposing the IF delay line output to the RF band.

Abstract: Disclosed herein is a system and method for determining a thickness of ice on Radio Frequency (RF) systems The system includes a sensor unit for use in determining the thickness of ice on a surface of a RADAR system having a RADAR antenna, the sensor unit including a sensor unit antenna tunable to a harmonic of a RADAR antenna signal, the harmonic having a frequency within an ice absorption band, wherein the sensor unit antenna emits the harmonic at a first signal strength; and, a sensor unit receiver communicatively coupled to the sensor unit antenna and configured to detect a second signal strength of the harmonic received by the sensor unit antenna.

Abstract: An optoelectronic oscillator (OEO) including a drift compensation circuit is provided. The OEO includes a set of optical domain components communicatively coupled with a set of RF domain components. The RF domain components include a mode selection filter, a phase locked loop (PLL) and a drift compensation circuit communicatively coupled between the mode selection filter and the PLL. The mode selection filter provides a mode selection result to the drift compensation circuit. The drift compensation circuit phase modulates the mode selection result in a vector based coordinate system to maintain a drift compensated mode selection result within a locking bandwidth of the PLL, and to minimize phase shifting from accumulating phase drift. The PLL detects a phase difference between the drift compensated mode selection result and a reference signal, for use in maintaining the PLL in a phase lock with the reference signal, in particular over wide operational temperature ranges.

Abstract: A delay device includes a tuning network including first and second tuning components having frequency responses that overlap in an intermediate frequency band to provide a group delay response. A delay modifier is in communication with the tuning network and configured to provide an offset frequency as an input to the tuning network, and to electronically adjust a group delay value associated with the group delay response by varying the offset frequency. The difference between a frequency of an input reference signal and a local oscillator frequency produced by the delay modifier is substantially equal to an intermediate frequency of the tuning network. The tuning network and the delay modifier cooperate to transpose the reference signal at the reference frequency down to the IF band before passing through the first and second delay lines, and back up to the RF band after passing through the first and second delay lines.

Abstract: A RADAR antenna system and method are provided. In an implementation, the system includes a base and first and second antennas configured to transmit independent first and second antenna beams, respectively. The first and second antennas are each coupled to the base so as to provide a common rotational axis for the first and second antennas. An antenna position controller is configured to independently control first and second transmission positions associated with the first and second antennas, respectively. Two different antenna technologies can be used, for example one for providing communications capability and the other for providing tracking capability. Other implementations include four or more antennas configured to transmit beams at similar or different frequencies. Improvements in scan rate proportional to the number of antennas are achieved compared to that achievable with a single beam, without an increase in the rotation rate of the antenna system.

Abstract: A solid state RADAR antenna system is provided comprising at least one antenna configured to transmit a plurality of antenna beams. Each antenna beam is decoupled from each of the other plurality of antenna beams for transmitting in a blind range of a different antenna beam. Accordingly, in an implementation, the second antenna beam is transmitted so as to scan a first blind range associated with the first antenna beam. Decoupling antenna beams can be achieved using one or more of physical decoupling using different antennas, frequency decoupling using different bands and/or frequency multiplexing, or orthogonal polarization.

Abstract: An optoelectronic oscillator (OEO) is disclosed comprising an electronically tunable filter for transposing narrow pass band characteristics of a surface acoustic wave (SAW) filter to a microwave frequency to provide mode selection in the OEO. An OEO is disclosed comprising a set of optical domain components, a downconverter in communication with an output of the optical domain components, and a set of radio frequency (RF) domain components in communication with an output of the downconverter. The set of RF domain components comprises a tunable filter operating at a filter center frequency and having an output coupled to the set of optical domain components for communicating a mode selection result. The tunable filter including a tuner; and a sub-filter. The sub-filter operating at a fixed center frequency to provide mode selection and adjacent mode suppression with respect to the tunable filter center frequency.

Abstract: An optoelectronic oscillator (OEO) is disclosed comprising an electronically tunable filter for transposing narrow pass band characteristics of a surface acoustic wave (SAW) filter to a microwave frequency to provide mode selection in the OEO. An OEO is disclosed comprising a set of optical domain components, a downconverter in communication with an output of the optical domain components, and a set of radio frequency (RF) domain components in communication with an output of the downconverter. The set of RF domain components comprises a tunable filter operating at a filter center frequency and having an output coupled to the set of optical domain components for communicating a mode selection result. The tunable filter including a tuner; and a sub-filter. The sub-filter operating at a fixed center frequency to provide mode selection and adjacent mode suppression with respect to the tunable filter center frequency.

Abstract: Circuits and methods for identifying or verifying frequencies are disclosed herein. A frequency verification circuit comprises: an input port for receiving an input signal; a phase frequency difference detector for determining a difference in phase and frequency between the input signal and a feedback signal and for providing a control signal based on the detected difference; a voltage controlled crystal oscillator for producing an output signal based on the control signal; and a feedback loop including a feedback divider for frequency dividing the output signal by a factor R to produce the feedback signal, the feedback divider being programmable to a plurality of values of the factor R to correspond to a plurality of different test frequencies.

Abstract: A digitally compensated phase locked oscillator (DCPLO) is disclosed herein. The DCPLO comprises: a DCPLO input for receiving a reference signal at a known frequency; a DCPLO output for outputting a signal at a desired frequency; a phased locked loop (PLL), the phased locked loop comprising: a phase frequency detector, an oscillator, and a PLL output coupled to the output; a first direct digital synthesizer (DDS), the first DDS having an output coupled to the PLL to supply a DDS signal to the PLL for adjusting the frequency within the PLL so as to maintain phase lock over the operating temperature; a temperature sensor; and a processor coupled to the first DDS, the phase frequency detector, and the temperature sensor, the processor configured to set the frequency of the first DDS according to a temperature sensed by the temperature sensor.

Abstract: A digitally compensated phase locked oscillator (DCPLO) is disclosed herein. The DCPLO comprises: a DCPLO input for receiving a reference signal at a known frequency; a DCPLO output for outputting a signal at a desired frequency; a phased locked loop (PLL), the phased locked loop comprising: a phase frequency detector, an oscillator, and a PLL output coupled to the output; a first direct digital synthesizer (DDS), the first DDS having an output coupled to the PLL to supply a DDS signal to the PLL for adjusting the frequency within the PLL so as to maintain phase lock over the operating temperature; a temperature sensor; and a processor coupled to the first DDS, the phase frequency detector, and the temperature sensor, the processor configured to set the frequency of the first DDS according to a temperature sensed by the temperature sensor.

Abstract: An offset phase locked loop synthesizer comprising: an input; an output; a voltage controlled oscillator (VCO), the VCO output coupled to the synthesizer output; a phase frequency detector having a reference input, a feed-back input, and an output; a mixer having a first mixer input coupled to the synthesizer input and a second mixer input coupled to the VCO output; a first divider for frequency dividing a signal by a first value and having an input coupled to the mixer output and an output coupled to the second input of the phase frequency detector; a second divider for frequency dividing a signal by a second value and having an input coupled to the synthesizer input and an output coupled to the reference input of the phase frequency detector; and a low pass filter coupled between the output of the phase frequency detector and the VCO input.