Electrical Balance Duplexer Antenna Sharing With Fixed Impedance

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Solution Overview

Problem

Conventional radar transceivers with electrical balance duplexers face challenges in achieving high spillover rejection across a wide bandwidth due to the need for complex impedance tuning and silicon-area intensive balance networks, which complicates antenna sharing in MIMO FMCW radars.

Innovation Solution

A radar transceiver employing a pre-tuned electrical balance duplexer with a non-tunable balancing impedance, comprising resistive, inductive, and capacitive elements, and a hybrid transformer network, which is designed to provide a fixed impedance value matching the antenna impedance, allowing for optimized balance conditions across frequencies without the need for complex tuning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a tunable balance network is used to achieve high spillover rejection, then the spillover rejection is improved, but the device complexity and tuning requirements increase

Engineering Contradiction:
Improvespillover rejectionVSAvoidbalance network complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The balance network is pre-tuned during manufacturing to match the antenna impedance at the center frequency. This preliminary action eliminates the need for complex runtime tuning mechanisms while maintaining high spillover rejection performance across the operating bandwidth.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the tuning function from the operational phase and moves it to the manufacturing phase. By taking out the dynamic tuning requirement and replacing it with a static pre-configured balance network, the device complexity is reduced while preserving the spillover rejection capability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If a wide bandwidth is achieved, then the adaptability is improved, but the spillover rejection deteriorates due to impedance mismatch across frequency

Engineering Contradiction:
Improveoperating bandwidthVSAvoidspillover rejection
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The balance network is optimized for local quality at the center frequency rather than uniform performance across the entire bandwidth. By concentrating the impedance matching precision at the center frequency where the antenna impedance is most critical, the patent achieves acceptable spillover rejection across a wide bandwidth without requiring complex wideband tuning mechanisms.

Inventive Principle:
Principle #3Local quality

3Reliability

If complex impedance tuning is implemented, then the spillover rejection is improved, but the manufacturing cost and time increase

Engineering Contradiction:
Improvespillover rejectionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The impedance matching is performed as a preliminary action during the manufacturing process rather than requiring complex post-assembly tuning. The balance network components are selected and configured to match the antenna impedance at the center frequency, enabling straightforward manufacturing without sophisticated tuning equipment or procedures.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables high spillover rejection with reduced physical dimensions, avoiding the complexities of impedance tuning and achieving sufficient spillover suppression across the operating bandwidth, facilitating compact and efficient antenna sharing in MIMO radar systems.

Implementation Method 1

an electrical balance duplexer (EBD) may be used to isolate a transmitter and a receiver and enable them to share a common antenna

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the non-tunable balancing impedance is configured to provide a fixed impedance value that is defined corresponding to an impedance at the antenna node

Methodology Applied
Scientific EffectImpedance matching: Electrical Impedance Tomography

Data Source

PatentEP4198551A1Radar transceiver and corresponding antenna sharing method using an electrical balance duplexer
Publication Date: 2023.06.21 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP4198551A1 patent drawingFigure 1
  • EP4198551A1 patent drawingFigure 2
  • EP4198551A1 patent drawingFigure 3

AI summary

A radar transceiver (100, 200, 300, 400) is provided. The radar transceiver comprises an electrical balance duplexer (109) coupled to a transmission node (106) of a transmission path, a reception node (108) of a reception path, and an antenna node (107), configured to isolate the transmission path from the reception path. The electrical balance duplexer (109) comprises a hybrid transformer network (110, 111) and a non-tunable balancing impedance (112). In this regard, the non-tunable balancing impedance (112) is configured to provide a fixed impedance value that is defined corresponding to an impedance value at the antenna node (107).