Embedded TX/RX Switch Using Common Impedance for Low-Loss Bandwidth
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Solution Overview
Problem
Conventional TX/RX switches suffer from significant power loss and limited bandwidth due to insertion losses and the use of quarter wavelength transmission lines, which degrade noise figure and output power efficiency, especially at higher frequencies, and occupy large die area in semiconductor chips.
Innovation Solution
The implementation of a TX/RX switch with a power amplifier output matching network, a Low-Noise Amplifier input matching network, and a mode switch that uses a common impedance in series-parallel combinations to optimize power transfer and noise figure, eliminating the need for transmission lines within semiconductor circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If quarter wavelength transmission lines are used in conventional TX/RX switches, then impedance matching is achieved, but insertion losses increase and bandwidth is limited
Solution Approach 1:
The patent removes the quarter wavelength transmission lines from the TX/RX switch circuitry, extracting the problematic impedance matching function and replacing it with direct switching mechanisms that connect the antenna to either the transmitter or receiver without intermediate transmission lines, thereby eliminating insertion losses while maintaining impedance matching
Solution Approach 2:
The switching mechanism is designed to perform both impedance matching and signal routing functions simultaneously, allowing the same switch structure to handle both tasks without requiring separate quarter wavelength transmission lines for each function, thus reducing overall insertion losses
2Manufacturing precision
If quarter wavelength transmission lines are used in TX/RX switches, then impedance transformation is achieved, but die area is occupied
Solution Approach 1:
The patent extracts and removes the quarter wavelength transmission lines from the semiconductor chip design, eliminating the need for large die area occupation while maintaining impedance transformation functionality through alternative switching mechanisms that require minimal space
Solution Approach 2:
The patent transitions from using physical transmission line length (spatial dimension) to achieve impedance transformation to using electrical switching states and circuit topology (electrical dimension) to accomplish the same function, thereby reducing the physical die area required
3Speed
If quarter wavelength transmission lines are used at higher frequencies, then signal transmission is achieved, but noise figure degrades and output power efficiency decreases
Solution Approach 1:
The patent removes the quarter wavelength transmission lines that cause frequency-dependent losses, enabling high frequency signal transmission without the degradation of noise figure and output power efficiency that occurs in conventional designs
Solution Approach 2:
The patent enables direct connection between the antenna and active components through the switching mechanism, allowing high frequency signals to pass through the switch without being subjected to the insertion losses and noise figure degradation that would occur through traditional transmission line paths
Data Source
AI summary
A TX/RX switch includes a power amplifier (PA), a Low Noise Amplifier (LNA), and an antenna connection. The PA is connected to a PA matching network that has a PA network impedance and a common PA-LNA impedance connected in one or more series-parallel combinations in different embodiments in a transmitting mode. The LNA is connected to a LNA matching network that has a LNA. network impedance and the same common PA-LNA impedance connected in one or more series-parallel combinations in a receive mode. A mode switch can connect the common PA-LNA impedance in different configurations to enable the transmitting and receiving mode respectively. In some embodiments, the mode switch can short or open circuit the connection of the PA matching circuit or the LNA matching circuit to the antenna. In some embodiments, the mode switch can also turn power on or off to the PA or the LNA when the switch is in a mode where the respective amplifier is not selected. Accordingly, with specific design limitations on the common PA-LNA impedance combined with different mode switch configurations of the TX/RX switch components in either the TX or RX mode, the TX/RX switch operates within a design bandwidth without, transmission lines embedded in the TX/RX switch circuitry and provides optimum power transfer from/to the antenna at the antenna connection with reduced noise.