Microstrip Coupler for Radar Transmit-Receive Signal Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional microwave and millimeter-wave automotive radar systems face inefficiencies due to half of the output power being wasted in ballast resistors and require large areas for separate transmitting and receiving antennas, making them unsuitable for miniature systems.
Innovation Solution
A single coupler system with a circular transmission path and 5 ports, where differential signals are converted to single-ended signals, allowing for efficient power distribution and reduced size through microstrip technology, enabling the use of a single antenna for both transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single antenna is used with a hybrid coupler for transmit-receive signal separation, then the system size is reduced, but power efficiency deteriorates due to 50% power loss in the ballast resistor
Solution Approach 1:
The invention segments the power distribution by using separate transmission and reception paths with individual power amplifiers and low noise amplifiers, allowing independent optimization of each path's power efficiency while maintaining single antenna operation
Solution Approach 2:
The invention extracts and removes the ballast resistor from the system entirely, replacing the hybrid coupler with a transmit-receive switch that directly connects the single antenna to either the transmitter or receiver without requiring a power-splitting hybrid component that dissipates 50% of the power
2Loss of energy
If two separate transmitting and receiving antennas are used, then power efficiency is improved, but the system area becomes too large for miniature radar applications
Solution Approach 1:
The single antenna serves dual functions as both transmitting and receiving antenna through time-division multiplexing controlled by the transmit-receive switch, eliminating the need for separate transmit and receive antennas while maintaining power efficiency through dedicated power amplifiers and low noise amplifiers for each function
Solution Approach 2:
The system dynamically switches the single antenna between transmission and reception modes using a transmit-receive switch, allowing the antenna to be optimally connected to either the power amplifier or low noise amplifier depending on the operational phase, thereby achieving both size reduction and power efficiency
3Adaptability or versatility
If a conventional hybrid coupler system is used, then transmit-receive signal separation is achieved, but device complexity increases due to multiple components including ballast resistors
Solution Approach 1:
The invention extracts and removes unnecessary components from the conventional hybrid coupler system, specifically eliminating the ballast resistor and the quadrature hybrid coupler itself, replacing them with a simpler transmit-receive switch that achieves the same signal separation function with fewer components
Solution Approach 2:
The invention merges the functions of the hybrid coupler and ballast resistor into a single transmit-receive switch component, combining signal routing and isolation functions into one active component that reduces overall system complexity while maintaining transmit-receive separation capability
Data Source
AI summary
One embodiment relates to a coupler that can be used in a radar system. The coupler includes differential ports, an antenna port, a receiver port, a local port and a transmission path. The differential ports are configured to receive a differential signal. The antenna port is configured to output a transmitted signal and to input a received signal. The transmitted signal is derived from the differential signal. The receiver port is configured to output a portion or version of the received signal. The local port outputs a local signal, which is also derived from the differential signal. The transmission path is coupled to the differential ports, the antenna port, the receiver port and the local port. The transmission path typically has a length selected to derive or output the signals at the above ports.