Antenna Switch Circuit Using Resonant Inductance for Power Handling
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Solution Overview
Problem
Conventional antenna switch circuits in wireless base-station applications face limitations in power handling and noise characteristics due to the need for high breakdown voltage switches and large transistor sizes, which increase circuit size, cost, and parasitic effects, and are often restricted to expensive Silicon on Insulator (SOI) technology.
Innovation Solution
An antenna switch circuit with a resonant inductance and a second switch coupled between a reference potential and a node between the resonant inductance and the receive port, allowing switches to be in an on state during transmit mode and off state during receive mode, eliminating the need for high breakdown switches and reducing circuit size by using bulk technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high breakdown voltage switches are used in conventional SPDT topology, then power handling capability is improved, but device complexity and circuit size increase
Solution Approach 1:
The patent segments the switch functionality by separating the high-power handling path (M1) from the high-voltage blocking path (M2). Switch M1 handles all transmit power while switch M2 only blocks reflected power, allowing each switch to be optimized for its specific function rather than requiring both to withstand full transmit power voltage.
Solution Approach 2:
The resonant inductance acts as an intermediary element that provides voltage blocking during transmit mode without requiring a high-voltage switch. The inductance creates a high impedance path that prevents reflected power from reaching the receive path, eliminating the need for switch M2 to withstand full transmit voltage.
2Power
If high breakdown voltage switches are used, then power handling is improved, but noise characteristics deteriorate due to larger transistor sizes
Solution Approach 1:
By segmenting the switch functions, the patent allows switch M2 to be a small transistor that only blocks reflected power during transmit mode, rather than being a large high-voltage switch. This segmentation enables optimization of each switch for its specific function, reducing overall noise while maintaining power handling.
Solution Approach 2:
The patent uses a small switch M2 that can be turned off completely during transmit mode, replacing the need for a large high-voltage switch. The resonant inductance provides the necessary voltage blocking function, allowing M2 to be a small, low-noise transistor that only needs to handle reflected power, not full transmit power.
3Power
If SOI technology is used for high breakdown switches, then power handling is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the operational parameters of conventional switches by introducing the resonant inductance that modifies the voltage and power distribution. This allows standard bulk technology switches to operate with reduced voltage stress, eliminating the need for expensive SOI technology while maintaining power handling capability.
Solution Approach 2:
The patent replaces expensive SOI high-voltage switches with standard bulk technology switches by using the resonant inductance to provide voltage blocking. This substitution maintains power handling capability while significantly reducing manufacturing cost through the use of cheaper bulk process technology.
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 solution enhances power handling and reduces noise characteristics, enabling a more compact and cost-effective design while allowing the use of bulk technology instead of expensive SOI, improving switching speed and reducing parasitic effects.
Implementation Method 1
a resonant inductance coupled between the receive port and the node located between the antenna port and the first switch
Data Source
AI summary
An antenna switch circuit and an antenna circuit switching method. The circuit includes an antenna port, a termination port (e.g., for disposal of power reflected back from an antenna and received through the antenna port in a transmit mode), and a receive port (e.g., for receiving a signal from the antenna port via the antenna switch circuit in a receive mode). The circuit also includes a first switch coupled between the antenna port and the termination port. The circuit further includes a resonant inductance coupled between the receive port and the node located between the antenna port and the first switch. The circuit also includes a second switch coupled between a reference potential and a node located between the resonant inductance and the receive port.