Detect-Only Rectenna Array for Fast RF Radiation Pattern Measurement
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Solution Overview
Problem
Conventional methods for measuring power radiated patterns in automotive radar systems are slow due to mechanical scans and require complex circuitry for switching between detect and reflect modes, degrading sensitivity with low gain antennas.
Innovation Solution
A rectenna array with zero-biased diodes and co-planar high gain antennas operates in detect mode only, eliminating the need for mechanical scans and switching circuits, allowing for fast power radiated pattern measurements and improved sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical scans are used to measure power radiated pattern, then measurement accuracy is maintained, but measurement speed becomes very slow
Solution Approach 1:
The patent replaces the mechanical scan system with an electronic rectenna array system. Instead of mechanically moving the probe antenna or DUT to scan spatial distribution, the invention uses multiple rectenna elements arranged in an array that can electronically detect radiated power in different directions simultaneously, eliminating mechanical movement and dramatically increasing measurement speed.
Solution Approach 2:
The patent transitions from one-dimensional mechanical scanning to a two-dimensional rectenna array configuration. The array elements are arranged in specific geometric patterns (such as circular or planar arrays) that enable simultaneous multi-directional detection, adding a spatial dimension to the measurement capability and eliminating the need for sequential mechanical scanning.
2Adaptability or versatility
If rectenna elements operate in both detect mode and reflect mode, then measurement versatility is improved, but system complexity and cost increase due to dedicated switching circuits
Solution Approach 1:
The patent extracts and removes the reflect mode functionality from the rectenna system, focusing exclusively on detect mode operation. By eliminating the reflect mode requirement, the patent removes the need for complex bias voltage switching circuits and mode control mechanisms, thereby reducing system complexity and cost while maintaining the essential measurement capability through the rectenna array's detect-only configuration.
3Reliability
If low gain patch antennas are used to support reflect mode, then radar cross section requirements are met, but sensitivity of the rectenna array degrades
Solution Approach 1:
The patent removes the reflect mode requirement that constrained antenna selection. Without the need to support reflect mode, the system can exclusively use high gain antennas in detect mode, thereby achieving superior sensitivity and measurement precision while maintaining adequate radar cross section performance through the array configuration rather than individual antenna reflectivity.
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
The system significantly speeds up power radiated pattern measurements and reduces system complexity and cost while maintaining high sensitivity by using fixed-bias diodes and high gain antennas.
Implementation Method 1
Each diode has a fixed zero bias, such that the diodes receive the incident RF signal through the antennas to which the diodes are respectively coupled, and rectify the incident RF signal to DC voltages that are proportional to power of the incident RF signal
Data Source
AI summary
A system is provided for measuring a power radiated pattern of an incident radio frequency (RF) signal indicating spatial distribution characteristics of a device under test (DUT). The system includes multiple antenna elements arranged in an array, where the antenna elements include antennas and diodes coupled to the antennas, respectively. Each antenna has a radar cross-section (RCS) that is too small for the antenna elements to operate in a reflect mode. Each diode is zero biased, such that the diodes receive the incident RF signal through the antennas to which the diodes are respectively coupled, and rectify the incident RF signal to DC voltages that are proportional to power of the incident RF signal, enabling the antenna elements to operate in a detect mode.