Hybrid Junction Module Feedforward Signal Leakage Compensation
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Solution Overview
Problem
Hybrid junction modules in transceivers face challenges in isolating receive ports from transmit ports due to impedance variations and coupling mechanisms, leading to signal leakage, especially in multi-band LTE systems where achieving wide bandwidth and low power loss is difficult without increasing complexity and cost.
Innovation Solution
A transceiver apparatus with a hybrid junction module and a feedforward circuit that selectively isolates or compensates for signal frequencies, using a noise cancellation circuit and programmable gain and phase adjustments to minimize leakage by favoring propagation of specific frequency bands, thereby reducing noise interference in the receive band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional duplexing filters (SAW filters) are used to isolate receive port from transmit port, then signal isolation is improved, but device complexity and cost increase due to requiring one filter per frequency band
Solution Approach 1:
The hybrid junction module is designed to support multiple frequency bands (e.g., LTE bands 3, 7, 8, 20) with a single device instance. The module uses broadband matching networks and adjustable impedance tuning to achieve isolation across multiple bands without requiring separate duplexing filters for each band, thereby reducing device complexity while maintaining signal isolation performance.
2Adaptability or versatility
If multiple discrete duplexers with RF switching are used to support multiple frequency bands, then frequency band coverage is improved, but signal power loss increases due to RF switch insertion
Solution Approach 1:
Multiple duplexer functions for different frequency bands are merged into a single hybrid junction module. The module uses broadband impedance matching networks and adjustable tuning elements to provide isolation across multiple bands (e.g., 1.8-2.7 GHz) without requiring RF switching between discrete duplexers, thereby eliminating switch insertion losses while maintaining multi-band support.
3Adaptability or versatility
If broadband hybrid junction is used to support multiple frequency bands, then frequency band coverage is improved, but signal leakage increases due to impedance variations and coupling mechanisms
Solution Approach 1:
The hybrid junction module incorporates adjustable impedance tuning elements (such as variable capacitors or inductors) that can be dynamically adjusted to optimize isolation performance across different frequency bands. This dynamic tuning compensates for impedance variations and coupling effects that occur in broadband designs, thereby reducing signal leakage while maintaining multi-band support.
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
Effectively compensates for noise signals leaking into the receive port from the transmit port, improving signal isolation and reducing interference, thus enhancing the performance of multi-band transceivers while maintaining low complexity and cost.
Implementation Method 1
a feedforward circuit arranged to be responsive in respect of a first transmit band of frequencies and a second transmit band of frequencies... favour propagation therethrough of signal frequencies in the second transmit band over signal frequencies in the first transmit band, thereby rendering a compensation signal
Implementation Method 2
a hybrid junction module having an antenna port, a transmit port, a receive port and a balance port; the hybrid junction module being arranged to isolate substantially the receive port from the transmit port
Implementation Method 3
an amplifier having a first input coupled to the receive port of the hybrid junction module, the amplifier comprising a noise cancellation circuit and a cancellation input operably coupled to the noise cancellation circuit and the output of the feedforward circuit; the amplifier being arranged to apply, when in use, via the noise cancellation circuit the compensation signal in order to remove signals in the second transmit band of frequencies
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A duplexing apparatus (100) comprises a hybrid junction module (204) having an antenna port (210), a transmit port (208), a receive port (206) and a balance port (212). The apparatus also comprises a feedforward circuit (230) arranged to be responsive in respect of a first transmit band of frequencies and a second transmit band of frequencies, the feedforward circuit (230) having an input operably coupled to the transmit port of the hybrid junction module and an output. The hybrid junction (204) is arranged to isolate substantially the receive port (206) from the transmit port (208) in respect of the first transmit band of frequencies and substantially not to isolate the receive port (206) from the transmit port (208) in respect of the second transmit band of frequencies. The feedforward circuit (230) is also arranged to favour propagation therethrough of signal frequencies in the second transmit band over signal frequencies in the first transmit band, thereby rendering a compensation signal at the output.