Linear Antenna Switch Arm Resistor Biasing
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Solution Overview
Problem
Existing antenna switch arms introduce non-linearities in high power signal transmission due to the highly non-linear shunt capacitance of FETs, which affects the linearity of the switched signal.
Innovation Solution
A linear antenna switch arm design featuring a series connection of FETs with resistors between input and output ports and at least one join node path, where the signal line and connection lines include resistors to maintain a floating bias and improve linearity, and optionally diodes for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple FETs are connected in series to handle high voltage, then the voltage swing is distributed across multiple junctions allowing high power transmission, but the non-linear shunt capacitance of each FET introduces non-linearities in the switched signal
Solution Approach 1:
Resistors are introduced as intermediary elements connected to the join nodes between FETs. These resistors act as mediators that provide a linearizing effect by controlling the voltage distribution across the FET junctions, thereby reducing the non-linearities introduced by the shunt capacitance while preserving the high voltage handling capability of the series-connected FETs
Solution Approach 2:
The invention changes the electrical parameters at the join nodes by connecting resistors that modify the voltage distribution and impedance characteristics. This parameter modification linearizes the overall response of the FET chain, transforming the highly non-linear shunt capacitance effect into a more linear signal transmission while maintaining the ability to handle high power signals
2Device complexity
If a single FET is used in the OFF arm, then the device complexity is low, but the bias voltage must be high to maintain the OFF state under high power conditions
Solution Approach 1:
The single FET structure is segmented into multiple series-connected FETs, each handling a portion of the total voltage. This segmentation allows the bias voltage requirement to be distributed across multiple devices, reducing the voltage stress on each individual FET and enabling the use of lower bias voltages while maintaining the OFF state under high power conditions
Solution Approach 2:
Multiple FETs are merged in series configuration to collectively handle the high voltage requirement. By combining multiple lower-voltage FETs, the system achieves the necessary voltage blocking capability without requiring a single high-voltage FET, thereby reducing the overall bias voltage requirement for each device while maintaining system functionality
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 design significantly enhances the linearity of the antenna switch arm, effectively managing high power signal transmission while maintaining a low bias voltage, thereby improving signal integrity.
Implementation Method 1
the signal line comprising at least one resistor between signal input and output ports; and the connection line comprising at least one resistor
Implementation Method 2
Field effect transistors are used to realise the series or shunt devices, the input being the drain and the output the source, or vice-versa. The signal passes through the conductive channel
Data Source
AI summary
A linear antenna switch arm comprisinga plurality of field effect transistors connected in series, the drain of each transistor being connected to the source of the next transistor at a join, the end source comprising one of a signal input or output port and the end drain comprising the complementary signal output port or input port;a signal line extending between the input and output ports;at least one of the joins being connected to the signal line at a node by a connection line;the signal line comprising at least one resistor between signal input and output ports; andthe connection line comprising at least one resistor.