Radar Antenna Array Drain Voltage Control Circuit
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Solution Overview
Problem
Conventional array antenna apparatuses for radar systems face challenges in reducing circuit scale and stabilizing RF pulse signal output due to complex circuit configurations and constant drain voltage of FETs, especially in aircraft-mounted radars where space and weight are limited, and the number of antenna elements can change during operation modes.
Innovation Solution
A common drain switching circuit and gate switching circuit are used to control the drain and gate voltages of power FETs in each antenna unit, allowing for selective output of RF pulse signals to individual antenna elements, reducing circuit scale and enabling adaptive operation mode changes by controlling voltage timing and switching speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high-speed switching circuit with multiple FETs is used to control drain voltage, then response speed characteristics are improved, but circuit complexity increases
Solution Approach 1:
The patent merges the drain voltage control function from individual per-element circuits into a single common drain switching circuit that serves all antenna elements. This common circuit uses a controlled number of FETs (first and second switching FETs) to regulate drain voltage for multiple elements simultaneously, reducing overall circuit complexity while maintaining high-speed response characteristics through coordinated switching control.
2Power
If a large capacitance capacitor is used in the power amplifier circuit to handle large high-voltage current, then power handling capability is improved, but circuit scale increases
Solution Approach 1:
The patent combines the power supply and capacitance functions into a common power supply circuit that serves all antenna elements. Instead of each element having its own large capacitance capacitor, a single power supply circuit with appropriate capacitance (first and second capacitors) provides the necessary high-voltage current to multiple elements, significantly reducing the total circuit scale while maintaining adequate power handling capability through shared resources.
3Device complexity
If drain voltage of FET is kept constant, then circuit simplicity is maintained, but output stability deteriorates when number of antenna elements changes
Solution Approach 1:
The patent implements dynamic drain voltage control through the common drain switching circuit. The drain voltage is no longer constant but is dynamically adjusted based on the number of antenna elements in use. The control circuit selectively activates the first and second switching FETs to regulate drain voltage to appropriate levels, ensuring stable RF pulse signal output regardless of whether all or only some antenna elements are operational, thus adapting to different operation modes.
4Adaptability or versatility
If RF pulse signal generation circuit is provided for each antenna element, then individual element control is improved, but circuit scale per antenna unit increases
Solution Approach 1:
The patent segments the control functions into different levels: individual antenna elements maintain their own gate switching circuits for element-specific control, while the drain voltage control and power supply functions are segmented out into common circuits that serve multiple elements. This hierarchical segmentation allows individual element control to be preserved where needed (gate control) while sharing common resources (drain voltage regulation and power supply) to reduce overall circuit scale per antenna unit.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
According to one embodiment, an antenna apparatus includes a plurality of amplifier circuits (20-n), a common drain control circuit (23), a gate control circuits (22-n), and an antenna controller (12). The common drain control circuit (23) constitutes a control circuit common to the plurality of amplifier circuits (20-n), and controls a drain voltage of a field-effect transistor included in each of the amplifier circuits (20-n). The gate control circuits (22-n) are provided for each amplifier circuit, and controls a gate voltage of the field-effect transistor. The antenna controller (12) controls the common drain control circuit (23) and the gate control circuits (22-n), and selectively operates the plurality of amplifier circuits (20-n) by controlling an output of the gate voltage prior to the drain voltage.