Half-Duplex Phased Array Antenna with SiGe Polarizer

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Solution Overview

Problem

Phased array antennas are limited by their frequency specificity, polarization inflexibility, and the need for separate radiating elements for transmit and receive functions, leading to increased complexity, cost, and reduced operational bandwidth.

Innovation Solution

A phased array antenna system with a half-duplex architecture using active components on silicon germanium (SiGe) that enables bidirectional operation, polarization agility, and simultaneous operation over multiple frequency bands, replacing traditional distributed components with compact, monolithic active components for power splitters, combiners, and phase shifters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional distributed components (phase shifters, power splitters, power combiners) are used in phased array antennas, then the antenna can perform transmit and receive functions, but the system complexity and cost increase significantly

Engineering Contradiction:
Improvetransmit and receive capabilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines transmit and receive functions into a single radiating element by using a circulator to separate transmit and receive signal paths. This eliminates the need for separate radiating elements for each function, reducing system complexity while maintaining full adaptability for both transmit and receive operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The radiating element is designed to serve multiple functions - it acts as both a transmit antenna and a receive antenna through the use of a circulator. This universal design allows a single element to perform what traditionally required separate dedicated elements, thereby reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If traditional distributed components are used, then the antenna can operate at specific frequencies, but the operational bandwidth is limited

Engineering Contradiction:
Improvefrequency specificityVSAvoidoperational bandwidth
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs electronically controllable phase shifters that can dynamically adjust the electrical length of transmission paths, enabling the antenna to operate across multiple frequency bands. This dynamic control allows the system to adapt to different frequency requirements without being restricted to a single fixed frequency operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By changing the electrical parameters (phase shift values) of the controllable phase shifters, the antenna system can adjust its resonant frequencies and operational characteristics. This parameter control enables wideband operation and multi-frequency capability while maintaining reliable performance at each specific frequency.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If GaAs materials are used for phase shifters and hybrids, then the performance is improved, but the manufacturing cost and difficulty increase

Engineering Contradiction:
Improveperformance qualityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive GaAs-based components with lower-cost alternative implementations. Specifically, it uses planar transmission line structures and integrated circuit techniques that can be manufactured more economically while achieving comparable performance through careful design of the transmission paths and phase control mechanisms.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention substitutes mechanical or discrete GaAs component assemblies with integrated planar transmission line structures. These transmission lines are fabricated using standard PCB or microwave substrate techniques, eliminating the need for expensive GaAs material processing and assembly, thereby significantly reducing manufacturing cost and complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of operation

If standard phase shifters with solid state circuits are used, then the phase control is achieved, but the RF power loss is high

Engineering Contradiction:
Improvephase control capabilityVSAvoidRF power loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces lossy solid-state circuit phase shifters with transmission line-based phase control mechanisms. By using controlled impedance transmission lines with adjustable electrical lengths, the system achieves phase control through geometric path differences rather than dissipative circuit elements, thereby minimizing RF power loss while maintaining full phase control capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2419962B1Half-duplex phased array antenna system
Publication Date: 2020.12.23 VIASAT INC
  • EP2419962B1 patent drawingFigure 1
  • EP2419962B1 patent drawingFigure 2
  • EP2419962B1 patent drawingFigure 3

AI summary

In an exemplary embodiment, a phased array antenna comprises a bidirectional antenna polarizer and is configured for bidirectional operation. The bidirectional antenna polarizer may combine active implementations of power splitters, power combiners, and phase shifters. Furthermore, in another exemplary embodiment a bidirectional antenna polarizer has extensive system flexibility and field reconfigurability. In yet another exemplary embodiment, the bidirectional phased array antenna operates in "radar-like" applications where the transmit and receive functions operate in half-duplex fashion. Furthermore, in exemplary embodiments, the phased array antenna is configured to operate over multiple frequency bands and/or multiple polarizations.