Phased Array Antenna Feeding Circuit Frequency-Independent Delay

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Solution Overview

Problem

Phased array antennas used in millimeter wave bands face challenges with frequency-dependent delay times, leading to beam direction changes with frequency, especially when using optical means, which are costly, and alternative configurations that delay intermediate or local signals result in frequency-dependent delays.

Innovation Solution

A phased array antenna configuration that includes multiple antenna elements, feeding circuits with time delay elements, demultiplexers, and transmission mixers to generate and supply delayed radio frequency signals, where the delay time is independent of frequency by adding and demultiplexing intermediate and local signals, ensuring consistent beam direction across frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical means are employed to impart time delay to radio frequency signals in millimeter wave band, then highly accurate time delay can be achieved, but cost increases significantly

Engineering Contradiction:

Improvetime delay accuracyVSAvoidcost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the optical system (which uses modulators and photoelectric conversion elements) with an electrical system that operates at intermediate frequency. The time delay is achieved through electrical signal processing at IF stage, avoiding the need for expensive optical components while maintaining delay accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the frequency parameter at which time delay is applied - instead of applying delay directly to RF signals or using optical means, the delay is applied to intermediate frequency signals. This parameter change allows the use of simpler, less expensive electrical components while achieving the required delay precision.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If intermediate frequency signal or local signal is delayed instead of radio frequency signal to reduce cost, then cost decreases, but delay time becomes dependent on frequency causing beam direction changes

Engineering Contradiction:

ImprovecostVSAvoidbeam direction consistency

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent applies time delay to the intermediate frequency signal before the signal is converted back to radio frequency. By performing the delay operation at the IF stage and maintaining this delay through the frequency conversion process, the beam direction remains consistent across different RF frequencies while avoiding the need for expensive optical components.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If RF-controlling phased array antenna configuration is used, then beam scanning function is achieved, but time delay cannot be accurately imparted to millimeter wave signals

Engineering Contradiction:

Improvebeam scanning capabilityVSAvoidtime delay accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies time delay to the intermediate frequency signal before frequency conversion to RF, ensuring that the delay is established in advance and maintained through the beam scanning operation. This preliminary delay application at IF stage enables accurate time control for millimeter wave signals without requiring direct RF delay circuits.

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 configuration allows for a phased array antenna with frequency-independent delay times, maintaining consistent beam direction across various frequencies, particularly in the 60 GHz and 70 GHz bands, enhancing beam scanning capabilities without the high costs associated with optical components.

Implementation Method 1

a time delay element configured to generate a delayed sum signal VIF+LO(t−Δti) by imparting a time delay Δti to the sum signal VIF+LO(t)

Methodology Applied

Scientific EffectTime delay:

Implementation Method 2

Each feeding circuit Fi is configured to supply the delayed radio frequency signal VRF(t−Δti) to a corresponding antenna element Ai

Methodology Applied

Scientific EffectFrequency mixing: Heterodyne

Data Source

PatentUS10862208B2Phased array antenna

Publication Date: 2020.12.08 FUJIKURA LTD

AI summary

Provided is a phased array antenna in which a delay time of a radio frequency signal supplied to each antenna element is not dependent on frequency. Each feeding circuit (Fi) of the phased array antenna (1) includes: a time delay element (TDi) configured to impart a time delay Δti to a sum signal VIF+LO(t) which is obtained by adding an intermediate frequency signal VIF(t) and a local signal VLO(t); a demultiplexer (DPi) configured to demultiplex a resulting delayed sum signal VIF+LO(t−Δti) so as to provide a delayed intermediate frequency signal VIF(t−Δti) and a delayed local signal VLO(t−Δti); and a transmission mixer (TMXi) configured to multiply the delayed intermediate frequency signal VIF(t−Δti) by the delayed local signal VLO(t−Δti) so as to provide a delayed radio frequency signal VRF(t−Δti), each feeding circuit Fi being configured to supply the delayed radio frequency signal VRF(t−Δti) to a corresponding antenna element (Ai).