Antenna-Transmitter Array Using Negative Impedance Converter

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Solution Overview

Problem

Current non-Foster matching systems for RF transmitters face challenges in achieving stable operation and efficient bandwidth due to inherent instability and the need for specially designed NIC loads, limiting their use in tunable RF antenna-transmitter systems.

Innovation Solution

A tunable RF antenna-transmitter system is designed using two antennas with a negative impedance converter (NIC) that eliminates the need for a specially designed NIC load, allowing for broader tuning and matching bandwidths and stable self-oscillations, enabling the use of different antenna types without redesign.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a passive matching network is used to match antenna impedance, then the system achieves stable operation, but the matching bandwidth is limited to 10-15% fractional bandwidth

Engineering Contradiction:

Improveoperational stabilityVSAvoidmatching bandwidth

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the fundamental parameter of the matching network from passive to active, introducing negative impedance converters that can provide negative capacitance and inductance. This parameter change enables the system to overcome the Bode-Fano bandwidth limitation and achieve fractional bandwidths exceeding 50%, while maintaining operational stability through proper design of the active matching network.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If non-Foster active matching is used to achieve broader bandwidth, then matching bandwidth increases significantly, but the system suffers from inherent instability and requires specially designed NIC loads

Engineering Contradiction:

Improvematching bandwidthVSAvoidoperational stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts and eliminates the requirement for specially designed NIC loads by using a different configuration where the antenna itself serves as one element of the matching network. This extraction removes the source of instability associated with traditional NIC loads while preserving the broadband matching capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using negative impedance converters to cancel antenna reactance (traditional approach), the patent inverts the approach by using the antenna's own reactance as a beneficial element in the matching network, combined with negative capacitance to achieve broadband matching without requiring unstable NIC load configurations.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If non-Foster matching with specially designed NIC loads is used, then bandwidth is improved, but the device complexity increases due to the need for customized load designs

Engineering Contradiction:

Improvematching bandwidthVSAvoidNIC load design complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal matching network configuration that can work with different antenna types without requiring customized NIC load designs. The active matching network using negative capacitance can be adapted to various antenna configurations, eliminating the need for specially designed NIC loads for each specific antenna type.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Device complexity

If conventional passive matching is used for small antennas, then the system is simple to implement, but the high reactance of small antennas significantly limits the achievable matching bandwidth

Engineering Contradiction:

Improvesystem simplicityVSAvoidmatching bandwidth

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by introducing active elements with negative capacitance to counteract the high reactance inherent in electrically small antennas. This enables broadband matching (fractional bandwidth >50%) for small antennas while maintaining relative system simplicity through a standardized active matching network design.

Inventive Principle:

Principle #35Parameter changes

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

The system achieves up to 3 dB higher effective radiated isotropic power and broader tuning bandwidths compared to prior art, with no need for a specially designed NIC load, allowing for flexible antenna usage and improved stability.

Implementation Method 1

a negative impedance converter (NIC) that eliminates the need for a specially designed NIC load, allowing for broader tuning and matching bandwidths and stable self-oscillations

Methodology Applied

Scientific EffectNegative Impedance Conversion:

Data Source

PatentUS10461440B2Antenna-transmitter array

Publication Date: 2019.10.29 UNIVERSITY OF ZAGREB

AI summary

A radiofrequency transmitter comprises a negative impedance converter having an input port and an output port; a first antenna electrically coupled to the input port of said negative impedance converter and operatively configured to emit electromagnetic radiation of a first polarization; and a second antenna electrically coupled to the output port of the negative impedance converter and operatively configured to emit electromagnetic radiation of a second polarization. The radiofrequency transmitter is operatively configured to emit an oscillating signal having a first frequency.