Dual-Capacitor Bias Network for Phased Array Noise Isolation
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Solution Overview
Problem
Phased array antenna systems face noise degradation in signal-to-noise ratio due to shared power buses during both transmit and receive modes, with existing bias networks failing to effectively isolate noise sources and provide clean bias power.
Innovation Solution
The introduction of a dual-capacitor bias network that switches between transmit and receive modes to charge and discharge capacitors independently, decoupling the array elements from common power sources and providing local energy storage to reduce noise impact, thereby improving noise performance and signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single capacitor is used to store energy for both transmit and receive functions, then device complexity is reduced, but noise from power bus coupling degrades signal-to-noise ratio
Solution Approach 1:
The single capacitor is segmented into two separate capacitors: a first capacitor coupled to the transmit amplifier and a second capacitor coupled to the receive amplifier. This segmentation allows independent energy storage and biasing for transmit and receive functions, preventing noise coupling between the two modes while maintaining clean power supply for each amplifier.
2Object-affected harmful factors
If local energy storage is implemented for each amplifier, then noise isolation is improved, but device complexity increases
Solution Approach 1:
The bias network merges the functionality of multiple capacitors into a unified structure where the first and second capacitors are coupled through a common node. This merging allows shared control and coordination between transmit and receive biasing while maintaining separate energy storage paths, reducing overall complexity compared to fully independent circuits.
Solution Approach 2:
The capacitor structure serves multiple functions: the first capacitor provides energy storage for transmit amplifier biasing, the second capacitor provides energy storage for receive amplifier biasing, and their coupling enables coordinated operation. This multi-functionality reduces the need for additional separate components while achieving noise isolation.
3Use of energy by moving object
If capacitors are charged during receive mode and discharged during transmit mode, then energy efficiency is improved, but bias pulse shaping becomes more difficult
Solution Approach 1:
The circuit utilizes changes in capacitor impedance and coupling strength during different operational modes to achieve proper bias pulse shaping. By adjusting the coupling parameters between the first and second capacitors and their respective amplifiers, the circuit automatically shapes the bias pulses without requiring external complex control circuitry, while maintaining efficient energy transfer during charge and discharge cycles.
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 effectively decouples noise sources, enhancing the signal-to-noise ratio by providing clean bias power to both transmitter and receiver components, improving the shaping of bias pulses and reducing noise corruption across the array elements.
Implementation Method 1
a capacitor CT selectively coupled to either: (1) a transmit power source here the transmit voltage source VT provided by the DC-DC converter during a receive mode; or (2) the transmit section, as shown in FIG. 1C during the transmit mode
Data Source
AI summary
An antenna element includes a bias network circuitry for: during a receive mode, charging a transmit supply capacitor from a transmit power source while decoupling a receive supply capacitor from a receiver power source and coupling the receive supply capacitor to discharge and thereby provide bias to the receiver; and during a transmit mode, charging the receive supply capacitor from the receive power source while decoupling the transmit supply capacitor from the transmit power source and coupling the transmit supply capacitor to discharge and thereby provide bias the transmitter. The antenna element includes a phase shifter/attenuator section having an amplifier and a phase shifter and wherein bias voltage is provided to the amplifier and phase shifter by the transmit supply capacitor during the transmit mode and the receive supply capacitor during the receive mode.