Radar Transceiver Module Switching Layout for Lower Noise Figure
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Solution Overview
Problem
Conventional transmitting-receiving modules in phased array radar systems suffer from high noise figures due to the insertion loss of multiple RF switches connected in series, which degrades the receiving system's performance and requires larger circuit sizes.
Innovation Solution
A transmitting-receiving module configuration that reduces the number of RF switches between the circulator and the low noise amplifier by using a 1-input 2-output RF switch and a 2-input 1-output RF switch, along with a fixed attenuator, to improve noise figure and miniaturize the circuit, while maintaining receiving system functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three RF switches are connected in series from circulator to low noise amplifier, then the receiving system can protect the low noise amplifier from destruction and handle excessive signals, but the noise figure becomes high due to insertion loss
Solution Approach 1:
The patent extracts one RF switch from the series connection between circulator and low noise amplifier, reducing the number of switches from three to two. This is achieved by reconfiguring the switch arrangement and using a through connector to directly connect the circulator output to the low noise amplifier input in certain operational modes, thereby reducing insertion loss and noise figure while maintaining the protection function through alternative signal paths.
Solution Approach 2:
The patent introduces a through connector as an intermediary component that provides a direct connection path between the circulator and low noise amplifier. This mediator allows the signal to bypass one or more RF switches when appropriate, reducing insertion loss and noise figure while still enabling protection functions through the remaining switch configuration.
2Reliability
If three RF switches are connected in series, then the receiving system functionality is maintained, but the circuit size becomes large
Solution Approach 1:
The patent removes one RF switch from the series connection, directly reducing the number of components and thereby reducing the circuit board area required. The extraction is achieved by reconfiguring the remaining two RF switches and through connector to perform the functions previously handled by three switches, resulting in a more compact circuit design.
Solution Approach 2:
The patent merges the functions of multiple components by using a through connector that provides direct connection capability, effectively combining the protection function and signal transmission function into a more integrated arrangement. This merging reduces the total component count and circuit footprint while maintaining full receiving system functionality.
Data Source
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AI summary
A transmitting-receiving module of a radar system which is an embodiment of the present invention, includes, a transmitting circuit for sending transmitting RF signal, a three terminal circulator having three terminals and with the first terminal of which is connected a transmitting-receiving antenna which transmits transmitting RF signal sent from the transmitting circuit and receives a receiving RF signal which is the reflected wave of the transmitted one, signal received by the transmitting-receiving antenna is outputted to the second terminal, signal inputted in the second terminal is outputted from the third terminal, a first RF switch which is connected with the second terminal of the three terminal circulator and the output can be switched over, a second RF switch with input which can be switched over, an attenuator connected between the first RF switch and the second switch, and a receiving circuit connected with the output terminal of the second RF switch, when radar signal is being transmitted, the first RF switch is connected with the attenuator, and the second RF switch is not connected with the attenuator, when radar signal is being received, the first RF switch is connected with the second RF switch directly or connected through a low noise amplifier.