Impedance-Gradient Duplexer for Low-Loss Receiver Isolation

Solution Overview

Problem

Existing wireless communication devices face insertion loss and interference due to the branching of transmission and reception paths through impedance tuners, leading to power loss and noise interference between transmitter and receiver circuits.

Innovation Solution

A frequency-dependent isolation circuit using multiple variable impedance devices is introduced, configured to operate in a balanced state to isolate the receiver from transmission signals and noise, while directing signals effectively between the transmitter, receiver, and antennas, thereby reducing insertion loss and maintaining signal isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an impedance tuner is used to match the impedance of the antenna, then the isolation between transmitter and receiver is improved, but insertion loss increases due to signal branching

Engineering Contradiction:

Improveisolation between transmitter and receiverVSAvoidinsertion loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the impedance matching function from a separate impedance tuner component and integrates it into the antenna element itself through an impedance gradient structure. This eliminates the need for a separate impedance tuner that would branch the signal path, thereby maintaining isolation while reducing insertion loss. The impedance gradient is formed by varying the width of the antenna element along its length, creating a continuous impedance transformation from the feed point to the radiating element.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the impedance matching function with the antenna radiation function by integrating the impedance gradient structure directly into the antenna element. This combination eliminates the separate impedance tuner component and its associated signal branching, allowing the antenna to perform both impedance matching and signal radiation simultaneously without additional insertion loss.

Inventive Principle:

Principle #5Merging (Combining)

2Power

If a power amplifier is used to amplify transmission signals, then transmission power is improved, but noise interference in the receive frequency band increases

Engineering Contradiction:

Improvetransmission powerVSAvoidnoise interference

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a spatially varying impedance distribution along the antenna element. The impedance gradient provides different impedance characteristics at different locations along the antenna, which enables frequency-selective behavior. This local variation in impedance helps to suppress noise signals at receive frequencies while maintaining efficient radiation at transmit frequencies, thereby reducing the harmful noise interference generated by the power amplifier.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the impedance parameter continuously along the length of the antenna element to create an impedance gradient. This parameter variation enables the antenna to present different impedance characteristics at different frequencies, allowing it to efficiently radiate transmit signals while simultaneously suppressing noise signals at receive frequencies, thus mitigating the noise interference problem.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the transmission path branches between the antenna and impedance tuner, then impedance matching is achieved, but signal power is lost

Engineering Contradiction:

Improveimpedance matchingVSAvoidsignal power loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the impedance matching function from a separate impedance tuner component and integrates it into the antenna element itself through an impedance gradient structure. This eliminates the need for a separate impedance tuner that would branch the signal path, thereby maintaining isolation while reducing insertion loss. The impedance gradient is formed by varying the width of the antenna element along its length, creating a continuous impedance transformation from the feed point to the radiating element.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs impedance matching in advance through the built-in impedance gradient of the antenna element, before the signal reaches any potential branching points. The continuous impedance transformation along the antenna length prepares the signal for efficient radiation without requiring subsequent impedance adjustment components that would create signal paths and additional loss.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12176877B2Single ladder duplexer with impedance gradient

Publication Date: 2024.12.24 APPLE INC

AI summary

Embodiments presented herein relate to isolating a receiver circuit of an electronic device from a transmission signal and from a noise signal at a frequency range of a received signal. To do so, an isolation circuit is disposed between the receiver circuit and a transmission circuit. The isolation circuit may include multiple variable impedance devices and one or more antennas. The impedances of the variable impedance devices and the one or more antennas may be balanced such that the receiver circuit is effectively removed from the transceiver circuitry and isolated from the transmission signal. The impedance of the variable impedance devices and the one or more antennas may also be configured to isolate the receiver circuit from a noise signal generated at the transmission circuit having a frequency in the range of the receive signal.