Retro-directive Array Using Orthogonal Polarizations for Low Power Tracking
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Solution Overview
Problem
Conventional retro-directive arrays for tracking systems face challenges in power consumption due to poor performance of CMOS circuitry at high frequencies, and building efficient transmit-receive switches with high isolation, low attenuation, and high speed is difficult, especially in consumer applications where millimeter-wavelength frequencies are used.
Innovation Solution
The use of orthogonal polarizations in a retro-directive array eliminates the need for frequency conversion and employs bi-directional quadrature gain modules and hybrid couplers to amplify quadrature signals, reducing power consumption and improving signal-to-noise ratio by making reflections from objects orthogonal to the desired signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional retro-directive arrays use frequency conversion with mixer and local oscillator at twice RF frequency, then tracking function is achieved, but power consumption increases significantly
Solution Approach 1:
The patent extracts and removes the frequency conversion stage (mixer and local oscillator) from the retro-directive array architecture. By directly using the received RF signal to drive the transmit array without frequency conversion, the design eliminates the primary sources of power consumption while maintaining the retro-directive tracking function through polarimetric beamforming.
Solution Approach 2:
The patent replaces the conventional electronic frequency conversion mechanism with a direct RF signal processing approach using polarimetric beamforming. Instead of converting frequencies through mixers and local oscillators, the system uses orthogonal polarization channels to achieve beam steering and retro-directive functionality, substituting a complex electronic conversion system with a more efficient signal processing method.
2Ease of operation
If transmit-receive switches operate at high frequencies for rapid switching between transmit and receive modes, then tracking circuitry function is achieved, but building efficient switches with high isolation, low attenuation and high speed becomes difficult
Solution Approach 1:
The patent extracts and removes the transmit-receive switching function from the system architecture. By using separate orthogonal polarization channels for transmit and receive operations, the design eliminates the need for rapid switching between modes, thereby removing the requirement for complex high-frequency switches while maintaining full-duplex tracking capability.
Solution Approach 2:
The patent introduces a polarization dimension to separate transmit and receive paths. By utilizing orthogonal polarizations (e.g., horizontal and vertical, or left and right circular polarization), the system creates independent channels that can operate simultaneously without interference, effectively adding a dimensional separation that eliminates the need for time-division switching.
3Device complexity
If CMOS circuitry operates at millimeter-wavelength high frequencies, then integration is achieved, but performance degrades and power burden increases
Solution Approach 1:
The patent extracts the high-frequency signal processing functions that would burden CMOS circuitry. By removing frequency conversion and switching operations from the integrated CMOS path and replacing them with direct RF processing using orthogonal polarizations, the design reduces the power burden on CMOS circuitry while maintaining integration benefits.
Solution Approach 2:
The patent changes the operating parameters of the CMOS circuitry by eliminating frequency conversion operations. Instead of requiring CMOS to handle complex mixer and local oscillator functions at high frequencies, the system reconfigures the signal path to use direct RF processing, thereby changing the operational demands on the CMOS circuitry to more manageable parameters.
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 approach minimizes power consumption, enhances signal-to-noise ratio, and facilitates efficient operation of transmit-receive switches with high isolation, enabling effective tracking in mobile applications without significant battery life impact.
Implementation Method 1
Tracking systems based on phase arrays have been used for many years in military radar applications... the only practical frequency band for such applications is in the millimeter-wavelength range... employs orthogonal polarizations to facilitate efficient operation
Implementation Method 2
employs bi-directional quadrature gain modules and hybrid couplers to amplify quadrature signals, reducing power consumption and improving signal-to-noise ratio by making reflections from objects orthogonal to the desired signal
Implementation Method 3
employs bi-directional quadrature gain modules and hybrid couplers to amplify quadrature signals
Data Source
AI summary
The disclosed embodiments relate to a retro-directive array that facilitates a tracking operation. This retro-directive array includes a first antenna configured to receive an input signal which is substantially circularly polarized from a tracking device. The first antenna separates the input signal into two signal components (e.g., Ex and Ey) associated with different orthogonal polarizations, wherein the two signal components comprise a quadrature signal wherein Ey=j·Ex. The retro-directive array also includes a bi-directional quadrature gain (BQG) module coupled to the first antenna which is configured to boost the quadrature signal. It additionally includes a second antenna which configured to transmit the boosted quadrature signal to the tracking device. The disclosed embodiments also relate to a transceiver switch, which includes: an input configured to receive a signal to be transmitted, and two phase mixers configured to receive the signal to be transmitted and phase inputs I and Q, and to produce a signal comprising two quadrature signal components SI and SQ, respectively, wherein SQ=j SI. The transmit switch also includes a hybrid coupler, which is configured to combine SI phase shifted by 180° with SQ phase shifted by 90° to produce a transmit output which is proportionate to S; and a switching mechanism configured to turn off the transmit output by swapping the phase inputs I and Q to the phase mixers.