High-Frequency PIN Switch Circuit for Antenna Isolation
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Solution Overview
Problem
RFID systems experience power losses due to electromagnetic coupling between antennas, which reduces the available power for communication, as the resonant frequency of inactive antennas changes when active antennas' fields couple with them, leading to incomplete opening of the antenna resonant circuit.
Innovation Solution
An electronic circuit using at least two PIN diodes for a high-frequency switch, where a rectifier circuit generates a blocking voltage from the high-frequency voltage to completely open the switch, with the blocking voltage routed through the same line as the high-frequency voltage, and a closing voltage is used to reopen the switch, ensuring the PIN diodes are fully blocked and the circuit is designed to maintain the open state for extended periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a high-frequency switch made of PIN diodes is used to open the antenna resonant circuit, then the switch can be controlled to open and close, but the switch cannot be completely opened due to insufficient blocking voltage, resulting in power losses
Solution Approach 1:
A rectifier circuit is introduced as an intermediary component to convert the high-frequency voltage into a blocking voltage that is sufficient to completely block the PIN diodes. The rectifier circuit acts as a mediator between the high-frequency voltage source and the switch, transforming the voltage characteristics to achieve complete switch opening while minimizing power losses.
Solution Approach 2:
The invention changes the voltage parameter by generating a blocking voltage with amplitude corresponding to at least the peak-to-peak value of the high-frequency voltage through the rectifier circuit. This parameter change ensures that the PIN diodes are completely blocked, achieving full switch opening and eliminating the previous insufficiency of the blocking voltage.
2Device complexity
If the blocking voltage is routed via the same electrical connecting line as the high-frequency voltage, then the circuit complexity is reduced, but the high-frequency voltage may interfere with the blocking voltage generation
Solution Approach 1:
A decoupling capacitor is introduced as an intermediary element on the shared electrical connecting line. This capacitor blocks high-frequency interference from affecting the blocking voltage generation while allowing the DC blocking voltage to pass through, thus resolving the interference issue without increasing overall circuit complexity.
Solution Approach 2:
The rectifier circuit generates the blocking voltage in advance from the high-frequency voltage before the switching operation. By preparing the blocking voltage beforehand and routing it through the same line, the system reduces complexity while the preliminary generation ensures the blocking voltage is ready and sufficient when needed, mitigating potential interference issues.
3Reliability
If a rectifier circuit is used to generate the blocking voltage from the high-frequency voltage, then the blocking voltage magnitude is sufficient to completely block the PIN diodes, but the rectifier circuit loads the high-frequency voltage source
Solution Approach 1:
The rectifier circuit is designed to generate just enough blocking voltage to completely block the PIN diodes (at least the peak-to-peak value of the high-frequency voltage), avoiding excessive voltage generation that would increase energy consumption. This partial action approach ensures sufficient blocking effectiveness while minimizing the load on the high-frequency voltage source.
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 solution effectively isolates inactive antennas, minimizing power losses and maintaining a fully open switch state, thereby ensuring maximum power availability for communication by generating a sufficient blocking voltage to completely block the PIN diodes and using a decoupling circuit to prevent interference with other components.
Implementation Method 1
a rectifier circuit, which is arranged outside of the antenna resonant circuit, which generates the blocking voltage for opening the high-frequency switch from the high-frequency voltage supplied
Implementation Method 2
the use of a high-frequency switch made of PIN diodes is provided for this purpose, it being possible for the PIN diodes to be blocked with the aid of a negative DC voltage, which is referred to below as blocking voltage
Implementation Method 3
a decoupling circuit is specified which prevents the possibly high blocking voltage from being able to impair or damage other components electrically connected to the circuit
Data Source
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AI summary
The circuit has a rectifier circuit (10) generating blocking voltage to open a high-frequency switch from a high-frequency supply voltage, where a value of the blocking voltage corresponds to a peak-to-peak value of a high-frequency voltage to be switched. The blocking voltage is conducted via am electric connecting line conducting the supply voltage and a closing voltage to an antenna, where the blocking voltage is injected with high impedance. Resistors are connected in parallel with respective positive-intrinsic-negative (PIN) diodes which are series-connected relative to direct current.