Bidirectional LO Injection for Image-Rejecting mmWave Arrays
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Solution Overview
Problem
Multi-band multi-standard wireless communication systems face challenges in mm-Wave transceiver frontend designs due to high power consumption and large chip area requirements for generating wideband local oscillator signals, particularly in 5G NR applications, which necessitate multiple phase locked loops and wide fractional bandwidths.
Innovation Solution
A bidirectional local oscillator signal generation approach is implemented, reducing LO requirements by using a single multiplier and RF phased locked loop circuit, enabling dual-polarization and bi-directional LO injection with high-side and low-side injections, and employing a shared PLL for reduced power consumption and phase noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple wideband power-hungry LO generation sets with several phase locked loops are used to generate wideband LO signals from 24 GHz to 43.5 GHz, then image rejection is achieved, but chip area and power consumption increase
Solution Approach 1:
The patent combines multiple LO generation functions into a single shared phase-locked loop that can operate across multiple frequency bands (24 GHz to 43.5 GHz). This single PLL replaces what would traditionally require multiple separate LO generation sets, thereby reducing power consumption while maintaining the ability to generate LO signals for wideband operation and image rejection across all bands.
Solution Approach 2:
The shared phase-locked loop is designed to be multi-functional, serving multiple frequency bands (24/28/37/39/43.5 GHz) and multiple standards (5G NR, E-band) with a single device. This universal LO generation approach eliminates the need for band-specific LO generators, reducing overall power consumption while maintaining comprehensive image rejection capability across all operating frequencies.
2Reliability
If multiple wideband power-hungry LO generation sets with several phase locked loops are used to generate wideband LO signals, then image rejection is achieved, but chip area increases
Solution Approach 1:
The patent merges multiple LO generation circuits into a single shared phase-locked loop implementation. This consolidation reduces the total chip area required by eliminating redundant PLL circuits, frequency synthesizers, and associated support circuitry that would otherwise be needed for separate LO generation in each frequency band.
Solution Approach 2:
The shared PLL is designed as a universal frequency synthesizer that can generate LO signals for multiple frequency bands and communication standards. This multi-functional approach allows a single chip-area-efficient circuit to replace what would traditionally require multiple separate LO generation blocks, thereby reducing overall chip area while maintaining comprehensive image rejection.
3Use of energy by stationary object
If a single multiplier and RF phased locked loop circuit are used for bidirectional LO injection, then power consumption and chip area are reduced, but LO signal generation capability must cover wide frequency range
Solution Approach 1:
The phase-locked loop is designed with dynamic frequency tuning capability, allowing it to adaptively adjust its output frequency to cover the wide range from 24 GHz to 43.5 GHz. This dynamic operation enables a single PLL to replace multiple fixed-frequency LO generators, reducing power consumption and chip area while maintaining the versatility to support multiple frequency bands and communication standards.
Solution Approach 2:
The patent utilizes parameter changes in the PLL circuitry, including variable division ratios, adjustable feedback dividers, and tunable VCO ranges, to enable the single LO generation circuit to cover the wide frequency spectrum required for multi-band operation. These parameter adjustments allow the system to maintain adaptability across different frequency bands while using a power-efficient single PLL architecture.
Data Source
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AI summary
An RF frontend integrated circuit (IC) device comprises one or more RF transceivers to transmit and receive RF signals within a first frequency band and a second frequency band that is higher than the first frequency band. The RF frontend IC device further comprises a bidirectional LO signal generation circuit coupled to the one or more transceivers to generate a bidirectional LO signal. The bidirectional LO signal is injected between the first frequency band and the second frequency band. The bidirectional LO signal generation circuit is to perform a high-side LO injection for the RF signals within the first frequency band by injecting the bidirectional LO signal having an LO frequency higher than the first frequency band and to perform a low-side LO injection for the RF signals within the second frequency band by injecting the bidirectional LO signal having the LO frequency lower than the second frequency band.