Multi-Band IQ Receiver Circuit for Wideband Image Rejection
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Solution Overview
Problem
Next-generation 5G communication devices require a higher data rate and broader bandwidth, particularly at millimeter-wave frequencies, but existing low-IF receiver architectures face performance degradation due to lossy wideband IQ local oscillator generation, necessitating an on-chip receiver with wideband image rejection.
Innovation Solution
A multi-band image-reject receiver circuit design incorporating a low noise amplifier, poly-phase filter, and IQ mixer circuit with a differential in-phase and quadrature output port, coupled with a frequency synthesizer to generate and drive local oscillator signals, enhancing down-conversion performance across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-IF receiver architecture is used to avoid flicker noise and DC offset, then receiver performance is improved, but wideband IQ local oscillator generation becomes lossy degrading mixer performance
Solution Approach 1:
The receiver is divided into multiple independent frequency bands (24 GHz, 28 GHz, 37 GHz, 39 GHz), each with its own dedicated IQ mixer and local oscillator generation path. This segmentation allows optimization for each band without compromising overall performance, reducing the lossy wideband IQ generation by using band-specific narrowband generation instead of lossy wideband generation.
Solution Approach 2:
Each frequency band is assigned dedicated local oscillator generation resources and IQ mixer circuits with optimized characteristics for that specific band. This local quality approach ensures that each band receives the appropriate quality and type of signal processing, avoiding the performance degradation that occurs when a single wideband path is used for all bands.
2Productivity
If millimeter-wave frequency is used to support higher data rate, then data rate capability is improved, but bandwidth requirements increase requiring broader frequency coverage
Solution Approach 1:
The receiver employs a universal architecture that can operate across multiple millimeter-wave frequency bands (24, 28, 37, and 39 GHz) using the same fundamental receiver structure. Each band shares common functional blocks while having band-specific components, providing multi-functionality that supports both high data rates and broad bandwidth coverage without requiring separate receivers for each band.
3Area of stationary object
If on-chip integration is implemented for wideband image rejection, then device compactness is improved, but circuit complexity increases at millimeter-wave frequency
Solution Approach 1:
The receiver implements nested frequency conversion stages where each band's IQ mixer downconverts to a common intermediate frequency, which is then processed by shared baseband circuits. This nesting allows multiple frequency bands to be handled within a unified on-chip architecture, reducing overall device area while managing the complexity through hierarchical signal processing.
Data Source
AI summary
According to one embodiment, a radio frequency (RF) receiver circuit includes a low noise amplifier, a poly-phase filter, and an in-phase quadrature (IQ) mixer circuit coupled between the low noise amplifier and the poly-phase filter. The IQ mixer circuit includes an IQ generator having a differential in-phase input port, a differential in-phase output port, and a differential quadrature output port; a first frequency mixer having a differential local oscillator (LO) input port, where the differential LO input port of the first frequency mixer are coupled to the differential in-phase output port of the IQ generator to drive the first frequency mixer; and a second frequency mixer having a differential LO port, where the differential LO input port of the second frequency mixer are coupled to the differential quadrature output port of the IQ generator to drive the second frequency mixer.