Passive CMOS Image Reject Mixer for High-Frequency Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current image reject mixers struggle to operate efficiently at high frequencies due to high power consumption and the need for expensive, esoteric manufacturing technologies like GaAs, while cost-effective CMOS technologies are not adequately utilized for frequencies in the tens of GHz range.
Innovation Solution
A fully passive image reject mixer is implemented using a pair of quad MOS multipliers and lumped-element hybrids, which function as both a band-pass filter and image rejection apparatus, eliminating the need for bias current and operational amplifiers, and allowing operation up to several tens of GHz with reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If GaAs manufacturing technology is used to achieve high-frequency operation, then frequency capability is improved, but manufacturing cost and power consumption increase
Solution Approach 1:
The invention changes the operating parameters by using passive mixing techniques with lumped-element hybrids operating at 90 degrees, enabling CMOS technology to achieve high-frequency operation (tens of GHz) without the high power consumption associated with active GaAs components. The passive nature of the mixer reduces power requirements while maintaining frequency capability.
2Speed
If GaAs manufacturing technology is used to achieve high-frequency operation, then frequency capability is improved, but manufacturing cost increases
Solution Approach 1:
The invention replaces expensive GaAs manufacturing with cheaper CMOS technology. By using standard CMOS processes with passive components (lumped-element hybrids, resistors, capacitors), the design achieves high-frequency operation without requiring costly specialized manufacturing, making mass production economically viable.
3Ease of manufacture
If CMOS technology is used to reduce manufacturing cost, then ease of manufacture is improved, but frequency capability deteriorates
Solution Approach 1:
Instead of using active components that require bias currents (conventional approach), the invention inverts the approach by using fully passive mixing with lumped-element hybrids. This inversion eliminates the frequency limitations of CMOS active devices while maintaining cost-effectiveness, achieving tens of GHz operation in standard CMOS.
4Ease of operation
If active components are used in image reject mixers, then mixing function is achieved, but power consumption and device complexity increase
Solution Approach 1:
The invention extracts and eliminates the bias current requirement from the mixer design by removing active components. The lumped-element hybrids and passive switching elements perform the mixing function without requiring operational amplifiers or continuous bias currents, significantly reducing power consumption while maintaining the image reject mixer functionality.
Data Source
AI summary
A passive implementation of an image reject mixer (IRM), capable of operating at very high frequency, is manufactured in a variety of silicon processes. The IRM comprises a quad MOS multiplier and a lumped-element hybrid, resulting in a passive IRM, operative at radio frequencies (RF) of tens of GHz with an intermediate frequency (IF) of several GHz. The RF+ and RF− signals are provided to two quad MOS multipliers. A local oscillator signal (LO) is used to provide LO+ and LO− signals to one of the multipliers and by providing the LO to a phase shifter, generated are a ninety degree shifted LO+ and LO− signals provided to the other multiplier. Providing the hybrids with the outputs of both multipliers and selecting an appropriate IF signal from each of the hybrids ensures the proper operation of the passive IRM.