Multibeam Radar Mixer Phase Switching for Wider Angle Estimation
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Solution Overview
Problem
Monostatic multi-beam radar sensor devices for motor vehicles face challenges in achieving ideal isolation in mixer cells, leading to leakage of transmission power and uncontrollable phase shifts, which affect the directional characteristic and angle estimation range.
Innovation Solution
The implementation of a Gilbert cell mixer with separate current sources for switching transistor pairs allows controlled phase switching between 0° and 180° of the overcoupling signal, enabling a switchable directional characteristic and cumulative transmission diagram, thereby improving isolation and reducing adjacent lane interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-ideal isolation of mixer cell is used, then transmission power leaks to reception channel, but directional characteristic cannot be controlled
Solution Approach 1:
The patent applies dynamics by making the phase position of the overcoupling signal switchable between 0° and 180°, transforming a static mixer cell into a dynamic system that can adapt its directional characteristic. The switching transistor pairs (12a, 12b) with separate current sources (14a, 14b) enable controlled phase switching, allowing the system to dynamically adjust between different operational states despite the inherent non-ideal isolation.
2Measurement precision
If phase position of overcoupling signal is not controlled, then angle estimation range is limited, but adding control increases device complexity
Solution Approach 1:
The patent applies segmentation by dividing the current supply for the switching transistor pairs into separate current sources (14a, 14b) instead of using a single common current source. This segmentation enables independent control of each transistor pair's phase position, allowing precise angle estimation through controlled phase switching between 0° and 180° without requiring a completely redesigned complex control system.
3Object-affected harmful factors
If outer radar beam lobes use reduced transmission power, then adjacent lane interference is reduced, but isolation between channels must be improved
Solution Approach 1:
The patent converts the harmful overcoupling signal leakage into a beneficial controllable phase signal. Instead of viewing the non-ideal isolation and resulting overcoupling signal as purely harmful, the invention utilizes this signal by controlling its phase position between 0° and 180° to create switchable directional characteristics. This allows the system to benefit from the overcoupling effect while maintaining reduced adjacent lane interference through controlled phase manipulation.
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 enhances the angle estimation range by allowing controlled phase manipulation, reducing the impact of manufacturing fluctuations and achieving significant amplitude differences, potentially expanding the angle estimation range and improving system performance.
Implementation Method 1
a mixer system (4) which has an at least approximately isolating mixer (9), in particular a Gilbert cell mixer, which, due to non-ideal isolation, in particular of its mixer cell, emits a transmission power between an input of a local oscillator signal (LO) or a local oscillator signal feed and the corresponding reception channel
Implementation Method 2
the switching transistor pairs (12a, 12b) of the Gilbert cell mixer (9) being fed separately by their own current sources (14a, 14b), the respective own current sources (14a, 14b) being used specifically to control the phase position of the overcoupling signal (10) between 0° and 180°
Implementation Method 3
a monostatic multi-beam radar sensor device for a motor vehicle with a directional characteristic of an antenna device (3) having at least one transmission/reception channel (TX)
Implementation Method 4
The mixed product then represents an intermediate frequency signal, the frequency of which indicates the frequency difference between the transmitted and the received signal. This intermediate frequency signal provides information about the Doppler shift that occurred when the transmitted signal was reflected at the radar target and thus about the relative speed of the radar target
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A monostatic multibeam radar sensor device for a motor vehicle, having a directional receiving characteristic comprising at least one send/receive channel (TX) and at least one receive channel (RX) of an antenna apparatus (3) and having a mixer system (4), which has an at least approximately isolating mixer for at least one of the receive channels (RX). The at least approximately isolating mixer has a Gilbert cell mixer (9), which, induced by non-ideal isolation between an input of a local oscillator signal (LO) and the corresponding receive channel (RX) emits transmitting power by way of said channel via an overcoupling signal (10), said transmitting power influencing the directional receiving characteristic of the antenna apparatus (3), wherein the directional receiving characteristic can be switched by controlling the phase position of the overcoupling signal (10).