mmWave Receiver LO Spur Cancellation Using Quadrature Paths
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Solution Overview
Problem
Millimeter wave (mmW) receivers face issues with spurious local oscillator (LO) signals, known as spurs, which can leak through circuitry and render certain frequency combinations unusable, degrading communication performance.
Innovation Solution
Implementing a mmW receiver design with a local oscillator generator, phase shifters, mixers, and a combiner element to generate LO signals out of phase, allowing for spur suppression by canceling out harmonics through shared power connections, and using switchable dummy paths to conserve power when suppression is not needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple LO signals are used in mmW receiver, then communication performance is improved, but spurious signals are generated that degrade performance
Solution Approach 1:
The patent applies the principle of converting harm into benefit by using the spurious signals themselves as cancellation references. The LO signals that generate spurs are fed into additional mixer paths where they produce spur copies that are then subtracted from the main signal path, transforming the harmful spurs into useful cancellation references that improve overall communication performance.
Solution Approach 2:
The receiver is segmented into multiple parallel signal paths: a main path for normal signal processing and additional suppression paths for spur cancellation. Each path processes the LO signals independently, allowing the spurious components to be isolated, processed, and subtracted without affecting the main communication signal quality.
2Object-generated harmful factors
If spur suppression circuitry is always active, then spurious signals are suppressed, but power consumption increases
Solution Approach 1:
The spur suppression circuitry is implemented as dynamically controllable rather than statically fixed. Switches and control logic enable the suppression paths to be activated only when spurious signals are detected or when specific frequency combinations are in use, allowing the system to adapt its power consumption to actual operational needs while maintaining suppression effectiveness when required.
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 suppresses spurious signals, improving communication device performance by reducing noise and maintaining power efficiency in complex carrier combinations.
Implementation Method 1
a 90-degree phase shifter having an output and an input coupled to the second output of the splitter
Implementation Method 2
a 180-degree phase shifter having an output and an input coupled to the output of the second mixer
Implementation Method 3
a first mixer having an output, a first input coupled to the RF input, and a second input coupled to the first output of the splitter, a second mixer having an output
Implementation Method 4
a combiner element having an intermediate frequency (IF) output, a first input coupled to the output of the first mixer, and a second input coupled to the output of the 180-degree phase shifter
Data Source
AI summary
Aspects of the disclosure relate to devices, wireless communication apparatuses, methods, and other aspects of spur suppression in millimeter wave receivers. In one aspect a local oscillator (LO) source is coupled to a quadrature generation circuit having a first output for a first LO signal, and a second output for a second LO signal 90 degrees out of phase with the first LO signal. Each output is coupled to an LO driver, and outputs of the LO drivers a coupled at a first power connection to provide spur suppression associated with a phase difference between the first LO signal and the second LO signal. Similar connections are provided at outputs of first and second mixers for spur suppression.