Hybrid Coupler T/R Switching Without Series Switch Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing TDM systems using T/R switches introduce signal loss and mismatch due to ON resistance and OFF capacitance, affecting system performance.
Innovation Solution
A circuit arrangement utilizing a balanced amplifier with an output hybrid coupler performing the task of a T/R switch, along with a set of switches to control the hybrid coupler's operation, eliminating the need for a series-connected T/R switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a series-connected T/R switch is used to connect/disconnect transmit and receive paths to the antenna, then switching between transmit and receive modes is achieved, but signal loss and mismatch occur due to ON resistance and OFF capacitance
Solution Approach 1:
The invention extracts the T/R switching function from a separate series-connected switch component and integrates it into the hybrid coupler structure itself. The hybrid coupler's inherent isolation port and switching mechanisms are utilized to perform T/R switching without requiring an external series switch, thereby eliminating the signal loss and mismatch caused by ON resistance and OFF capacitance of separate switches.
Solution Approach 2:
The invention merges the T/R switch functionality with the hybrid coupler structure. By combining these functions into a single integrated component, the patent eliminates the need for separate series-connected switches that cause signal loss, while maintaining effective transmit/receive mode switching through the hybrid coupler's isolation port and associated switching mechanisms.
2Object-affected harmful factors
If a series-connected T/R switch is used to protect the receive path from high power transmit signals, then isolation is achieved, but insertion loss increases due to switch resistance
Solution Approach 1:
The invention uses the hybrid coupler's isolation port as an intermediary element to protect the receive path from high power transmit signals. Instead of relying on a series switch that introduces resistance and loss, the isolation port provides natural isolation between transmit and receive paths, with switching control achieved through the hybrid coupler's inherent structure and associated switches.
3Ease of operation
If traditional T/R switch design is used, then transmit and receive paths can be switched, but the design becomes less compact and performance advantages of balanced amplifiers are reduced
Solution Approach 1:
The invention merges multiple functions (hybrid coupling, T/R switching, and balanced amplifier operation) into a single integrated structure. This consolidation eliminates the need for separate series-connected switches and reduces overall circuit complexity, resulting in a more compact design that maintains full switching capability while preserving the performance advantages of balanced amplifiers.
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 reduces signal loss and mismatch, maintaining the performance advantages of balanced amplifiers while eliminating the negative effects of T/R switches, resulting in lower insertion loss and a more compact design.
Implementation Method 1
A hybrid coupler (350), also known as a quadrature coupler, provided at an input of the balanced amplifier (200), splits an input RF signal provided at an input node PAin of the amplifier, to two quadrature signals (i.e., 90 degrees apart) of substantially same power
Implementation Method 2
one or more switches (EN_Tx, EN_Rx, configured, for example, as a SPDT switch) may be used to connect and disconnect an RF transmit path (110, . . . ) and an RF receive path (120, . . . ) to a common antenna (150)
Data Source
AI summary
A hybrid coupler-based T/R switch for use in a TDM system. An output hybrid coupler of a balanced amplifier is used to selectively switch a transmit or receive path to an antenna. During transmission, power at the output of the balanced amplifier is delivered directly to the antenna. During reception, power from the antenna is reflected through ports of the hybrid coupler connected to respective two amplifiers of the balanced amplifier, to constructively combine at a port of the coupler coupled to the receive path, with a ninety degrees phase shift. A pair of shunting switches or series switches coupled to the ports of the hybrid coupler connected to the two amplifiers, and a shunting switch coupled to the port coupled to the receive path, control operation of the hybrid coupler-based T/R switch. An additional switch coupled to the port of the coupler that is coupled to the receive path can provide a bypass path for reception or transmission through the antenna while bypassing the balanced amplifier of the transmit path and an amplifier of the receive path.