Baseband Phase Shifter for Low-Power Wireless Antenna Control
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Solution Overview
Problem
High-frequency wireless communication systems face power consumption issues due to the use of phase shifters with significant loss, leading to increased circuit size and power consumption, especially when controlling antenna radiation patterns in high-frequency bands.
Innovation Solution
A phase shifter design that adds phase information to baseband signals using a 90° step phase shifter and a 45° phase shifter, allowing for phase control without the need for a high-frequency phase shifter, thereby reducing power consumption by performing signal replacement and inversion of polarities based on specific phase information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a phase shifter for high-frequency band is used to control the phase of transmitted signals, then the radiation pattern can be controlled to establish communication through reflections, but the phase shifter introduces great loss requiring additional amplifiers which increases circuit size and power consumption
Solution Approach 1:
The patent introduces a baseband signal as an intermediary to transfer phase information. Instead of directly shifting the phase of high-frequency RF signals (which causes loss), the system generates baseband signals with the desired phase characteristics and uses these to modulate the RF signals. This intermediary approach allows phase control without the losses associated with high-frequency phase shifting.
Solution Approach 2:
The patent replaces the mechanical/high-frequency phase shifter with a baseband signal processing system. Rather than using physical phase shifters at RF frequencies that introduce loss, the system uses baseband signal generation and IQ modulation to achieve the same phase control effect, substituting a lower-frequency, lower-loss mechanism for the high-frequency one.
2Reliability
If the number of antennas is increased to improve radiation pattern control, then communication reliability through reflections is enhanced, but the power consumption in the phase shifter increases considerably
Solution Approach 1:
By using baseband signals as intermediaries, the patent enables efficient control of multiple antenna elements without proportionally increasing power consumption. Each antenna element can be controlled independently through its own baseband signal, allowing sophisticated radiation pattern control (including reflection paths) while maintaining lower power consumption compared to using high-frequency phase shifters for each element.
3Use of energy by moving object
If a Gilbert cell mixer is used in the phase shifter to achieve low power consumption, then power efficiency is improved, but current drive requirements increase the overall power consumption when multiple antennas are used
Solution Approach 1:
The patent replaces the Gilbert cell mixer architecture with a baseband signal generation approach. Instead of using current-driven mixing circuits that consume significant power when scaling to multiple antennas, the system generates phase-controlled signals at baseband and uses voltage-driven IQ modulators, which are more scalable and power-efficient for multi-antenna systems.
Data Source
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AI summary
The present invention has an object to provide a phase shifter, a wireless communication apparatus, and a phase control method in which power consumption is reduced. A phase shifter according to the present invention includes a 90° step phase shifter (17) and a 45° phase shifter (18) and adds phase information to two baseband signals to be output to an orthogonal modulator. The 90° step phase shifter (17) contributes to adding any one of phases 0°, 90°, 180°, and 270° to the baseband signals according to a first control signal. The 45° phase shifter (18) contributes to adding one of phases 0° and 45° to the baseband signals according to a second control signal. A phase shifter (8) performs replacement of component signals of one of the baseband signals with component signals of the other of the baseband signals and inversion of polarities of the component signals.