Absorptive RF Rectifier Circuit with Fishbone Topology
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Solution Overview
Problem
Rectifier circuits used to replace resistive dummy loads in RF systems often have narrow band responses and inject self-generated harmonics back into power amplifiers, leading to inefficiencies and energy loss.
Innovation Solution
The design of an absorptive RF rectifier circuit with a transmission line that includes series inductors and embedded RF-DC converters, which absorb energy and reduce return losses, mimicking resistive loads over a wide bandwidth, and features a fishbone topology with non-uniform inductance values to ensure equal voltage drive across diode pairs for efficient RF-to-DC conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If reflective rectifier circuits are used to replace resistive dummy loads, then energy recovery is improved, but narrow band response and harmonic injection worsen
Solution Approach 1:
The rectifier circuit is divided into multiple identical unit cells connected in series, each cell containing a rectifier diode and associated components. This segmentation allows the circuit to process broadband RF signals while distributing the rectification function across multiple stages, reducing harmonic injection and improving energy recovery across a wide frequency range.
Solution Approach 2:
The circuit parameters including inductance values, capacitance values, and impedance levels are specifically designed and optimized to achieve broadband operation. By carefully selecting and adjusting these parameters, the circuit maintains effective rectification across a wide frequency range while minimizing harmonic generation and injection.
2Loss of energy
If reflective rectifier circuits are used to replace resistive dummy loads, then energy recovery is improved, but broadband performance worsens
Solution Approach 1:
The rectifier circuit is divided into multiple identical unit cells connected in series, each cell containing a rectifier diode and associated components. This segmentation allows the circuit to process broadband RF signals while distributing the rectification function across multiple stages, reducing harmonic injection and improving energy recovery across a wide frequency range.
Solution Approach 2:
The rectifier circuit is designed with universal unit cells that can operate effectively across a wide frequency range, making the circuit adaptable to different RF signal conditions and applications. The multi-cell configuration provides both broadband response and efficient energy recovery simultaneously.
3Power
If conventional rectifier circuits are used, then RF-DC conversion is achieved, but return losses increase
Solution Approach 1:
The circuit introduces intermediate components including series inductors and shunt capacitors that act as mediators to improve impedance matching between the RF input and the rectifier diodes. These intermediary elements reduce signal reflections and return losses, enabling more effective power transfer and RF-DC conversion.
Solution Approach 2:
The circuit parameters including inductance values, capacitance values, and impedance levels are specifically designed and optimized to achieve broadband operation. By carefully selecting and adjusting these parameters, the circuit maintains effective rectification across a wide frequency range while minimizing harmonic generation and injection.
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 configuration achieves high RF-DC conversion efficiency and low return losses, reducing harmonic injection and thermal dissipation, allowing for effective energy recovery and operation similar to resistive dummy loads without altering amplifier systems.
Implementation Method 1
a rectifier circuit that converts a radio-frequency (RF) alternating current (AC) electrical energy into direct current (DC) energy
Implementation Method 2
a plurality of inductors connected electrically in series between an input node for receiving an input RF signal and a resistive termination
Data Source
AI summary
A radio frequency rectifier circuit may include a resistive termination to circuit ground, a plurality of inductors, and at least a first pair of rectifier components. The plurality of inductors may be connected electrically in series between an input node for receiving an input RF signal and the resistive termination. Each pair of electrically adjacent inductors of the plurality of inductors may be connected together at a respective in-line node. The first pair of rectifier components may electrically couple a first one of the in-line nodes to a respective direct current output node. Each rectifier component may have a cathode and an anode. A first rectifier component of the first pair of rectifier components may have the cathode electrically connected to the first in-line node and a second rectifier component of the first pair of rectifier components may have the anode electrically connected to the first in-line node.