Millimeter-Wave Transceiver LO Calibration for Low Phase Noise
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Solution Overview
Problem
Current millimeter-wave band radio transceiver devices face challenges in improving phase noise characteristics and calibrating local oscillators independently, particularly with injection-locked oscillators, which do not effectively address I/Q mismatching and require additional pilot signals and template data.
Innovation Solution
A millimeter-wave band radio transceiver device incorporating injection-locked oscillators in both transmitter and receiver units, with a calibration unit to adjust local oscillators using a reference frequency signal generator, and I/Q combination-type quadrature oscillators with symmetrically arranged mixers to reduce I/Q mismatch, allowing independent calibration and improved phase noise characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional local oscillator structures (frequency doubling, polyphase filter, or dual two-phase oscillators) are used to generate four-phase sine wave outputs, then the local oscillator can provide I/Q-component signals, but I/Q mismatching occurs and it is technically difficult to realize these structures
Solution Approach 1:
The patent divides the local oscillator function into two separate injection-locked oscillators: one dedicated to generating the I-component signal and another dedicated to generating the Q-component signal. This segmentation allows each oscillator to be independently calibrated and adjusted, eliminating the I/Q mismatching problem that plagues conventional integrated approaches. The segmentation principle is applied by creating independent oscillator units that can be separately tuned to ensure precise 90-degree phase difference and matching characteristics.
Solution Approach 2:
The patent introduces a reference frequency signal as an intermediary to both injection-locked oscillators. This reference signal serves as a common baseline that enables synchronized operation and precise phase relationship control between the I and Q component generators. By using the reference frequency signal as a mediator, the system achieves accurate I/Q matching without requiring complex calibration procedures.
2Device complexity
If injection-locked oscillator is used as local oscillator without calibration, then the circuit configuration is simplified, but the problem of I/Q mismatching cannot be solved
Solution Approach 1:
The patent implements preliminary calibration action by providing a calibration unit that adjusts the injection-locked oscillators before normal operation. The calibration unit uses a calibration signal to tune and match the I and Q component oscillators, ensuring precise phase relationships and matching characteristics are established in advance. This preliminary action resolves the I/Q mismatching issue while maintaining the simplicity of the injection-locked oscillator architecture during normal operation.
Solution Approach 2:
The calibration unit enables the local oscillator system to self-adjust and self-calibrate the injection-locked oscillators using internally generated calibration signals. This self-service mechanism allows the system to automatically correct I/Q mismatching without requiring external intervention or complex manual calibration procedures, maintaining operational simplicity while achieving precise matching.
3Reliability
If conventional radio transceiver device requires calibration for I/Q mismatch, then communication quality can be improved, but additional pilot signals and template data are required increasing device complexity
Solution Approach 1:
The patent performs preliminary calibration of the injection-locked oscillators using a calibration unit that adjusts the oscillators based on calibration signals before normal communication operation begins. By completing the calibration action in advance, the system eliminates I/Q mismatching issues before they affect communication quality, removing the need for continuous pilot signal processing and template data matching during operation. This preliminary action reduces device complexity while maintaining high communication reliability.
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 enables independent calibration of local oscillators and reduces phase noise, effectively addressing I/Q mismatching and enhancing communication quality in millimeter-wave band radio transceivers.
Implementation Method 1
an injection-locked oscillator that oscillates at a frequency that is in synchronization with and an integer multiple of an injected reference frequency signal
Implementation Method 2
an upconversion mixer which mixes a signal from the local oscillator for upconversion with a baseband signal for transmitter
Implementation Method 3
a downconversion mixer which mixes a signal from the local oscillator for downconversion with a signal from the amplifier for receiver to output a baseband signal for receiver
Data Source
AI summary
Provided is a millimeter wavelength range transceiver device which can improve phase noise characteristics and which can also independently calibrate each respective local oscillator of a transmission unit and a reception unit. This millimeter wavelength range transceiver device comprises a transmission unit (10), a reception unit (20), and a reference frequency signal generator (30). The transmission unit (10) comprises a transmission-use local oscillator (11) comprising an injection-locked oscillator, a transmission-use mixer (12) for mixing the signal from the transmission-use local oscillator and a transmission baseband signal, and a transmission-use amplifier (13) for amplifying the signal from the transmission-use mixer to a transmission-use antenna (15). The reception unit (20) comprises a reception-use amplifier (25) for amplifying a signal from a reception-use antenna (24), a reception-use local oscillator (22) comprising an injection-locked oscillator, and a reception-use mixer (23) for mixing the signal from the reception-use local oscillator and the signal from the reception-use amplifier in order to output a reception baseband signal. A reference frequency signal generator (30) injects a reference frequency signal into the transmission-and-reception-use local oscillators (11 and 22).