Steerable FMCW Radar Transceiver With Circular Polarization
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Solution Overview
Problem
Current microwave and millimeter-wave integrated circuits for radar systems face challenges in simultaneous transmission and reception of signals, particularly in achieving phased-array beam steering and accurate distance and velocity measurement, due to limitations in signal phase control and frequency modulation.
Innovation Solution
The development of a dual-orthogonally polarized antenna assembly with a transceiver system that includes transmit and receive phase shifting circuits, power amplifiers, and mixers, capable of generating circularly polarized waves and performing phased-array beam steering, allowing for simultaneous transmission and reception of signals and accurate distance measurement through frequency modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phased-array beam steering is implemented using traditional integrated circuits, then beam direction control is achieved, but signal phase control precision and simultaneous transmit/receive capability are limited
Solution Approach 1:
The patent divides the phased array into multiple independent transceiver units, each capable of autonomous phase control. This segmentation allows precise phase adjustment at each element while maintaining overall beam steering capability, resolving the contradiction between adaptability and precision.
Solution Approach 2:
The patent introduces a third dimension by implementing full-duplex simultaneous transmit and receive capability in addition to beam steering. This allows the system to operate in multiple dimensions (spatial beam direction and temporal transmit/receive mode) concurrently, enhancing adaptability without compromising phase control precision.
2Adaptability or versatility
If frequency modulation is used for distance and velocity measurement, then measurement capability is provided, but measurement accuracy is limited by circuit performance
Solution Approach 1:
The patent implements feedback mechanisms where received signals are processed and used to adjust transmit parameters. This feedback loop enhances measurement precision by continuously optimizing the frequency modulation based on actual target responses, while maintaining versatile measurement capability for both distance and velocity.
3Device complexity
If integrated circuits are used for radar signal processing, then system integration is achieved, but simultaneous transmission and reception performance is degraded
Solution Approach 1:
The patent introduces intermediate frequency conversion stages as mediators between transmit and receive paths. This allows simultaneous operation by separating the frequency domains, enabling integrated circuit implementation while maintaining reliable simultaneous transmit and receive performance through frequency isolation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient phased-array beam steering and accurate range and velocity determination by effectively combining in-phase and quadrature-phase signals, enhancing the performance of microwave and millimeter-wave radar systems.
Implementation Method 1
a transmit phase shifting circuit in the transceiver, configured to apply a phase shift to a transmit signal from a local oscillator
Implementation Method 2
a power amplifier in the transceiver coupled to the transmit phase shifting circuit, having a differential output
Implementation Method 3
with a first port coupled through a first isolation coupler to a first polarity terminal
Implementation Method 4
with a second port of the differential output coupled through a second isolation coupler and a 90-degree phase delay
Implementation Method 5
the in-phase and quadrature-phase signals at the antenna assembly terminals forming a circularly polarized electromagnetic wave
Implementation Method 6
a low noise amplifier in the transceiver, with an input terminal coupled to the output terminal of the power combining circuit, and an output terminal, configured to amplify a received circularly-polarized signal
Implementation Method 7
a first mixer having a first input coupled to the first isolation coupler and a second input coupled to the output of the low noise amplifier, configured to output a difference signal
Implementation Method 8
a receive phase-shifting circuit having an in-phase input coupled to the first mixer to receive the in-phase difference signal and having a quadrature phase input coupled to the second mixer
Data Source
AI summary
Apparatus, method, and system example embodiments provide an improved integrated circuit RF front end to simultaneously transmit and receive signals for radar imaging. In an example embodiment, an apparatus comprises a transceiver coupled to a circularly polarized antenna assembly, capable of transmitting circularly polarized signals that are a component of a multi-signal radar beam; a power amplifier configured to amplify a transmit signal, coupled through isolation couplers to the circularly polarized antenna assembly; a phase shifting block circuit configured to perform phase shifting of a local oscillator signal, in response to the receipt of phase control signals, to perform phased-array beam steering of the multi-signal radar beam when the component circular signals are associated with signals transmitted from other transceivers receiving the phase control signals. The apparatus further includes a receiver circuit utilizing a receive phase-shifting circuit coupled to a quadrature down-conversion mixer, for receive beam steering.