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12 April 2010RAF#30301801

Design and Optimization of an Antenna

using CST Microwave Studio and Mode

Frontier

Missiles & NCW DivisionR & D and Engineering

Directorate

S. Poles, F. Bernasconi – Esteco , E. Leroux – CST , Y. Kaldor - Rafael

CST UGM2010 , Darmstadt 19-21 April 2010

UNC/8/30783/10

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The following slides describe the design process of a small antenna located on a large cylindrical platform.

The platform dimensions are : 13λ x 3λ x 3λ

Overview

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The Antenna is required to perform over a 30% Frequency Bandwidth.

Matching Specification – over the full Bandwidth:

Return Loss : -8 dB max

VSWR 2.2:1 max

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Tight Space – therefore required small antenna dimensions

The environmental conditions under which the antenna is required to perform are harsh.

Requirements

Difficulties

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The Solution

The antenna chosen as a solution is a

combination of a Slot Antenna and Travelling

Wave Antenna.

The Antenna was modeled and simulated

using CST Microwave Studio for return loss

and radiation pattern performance.

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Initial Simulation Results

Matching over the full

frequency range was nearly

impossible due to dimension

constraints and coupling

from the platform

Simulated Return loss was

initially very poor.

Sufficient performance was

obtained over 6% bandwidth

only.

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Specification

Optimization design Goal

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The parameterized CST model

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H

L

hp

r

Input port

Initially the parameters

which mostly effect the

matching performance

were identified.

The CST model was

regenerated using these

parameters.

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mF - Optimization WorkflowADVANCED DEFENCE

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R_loss_f_low

R_loss_f_cen

R_loss_f_high

Output Variables

Minimize(maximum) Maximum < -10 dB

Design Objective Design Constraint

slot_length

stub

r_stub

pin_dist

partstub

slot_h

Input Variables

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Bubble Chart

mF - Design SpacePost Processing

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mF - Design SpacePost Processing

Parallel Coordinate

Chart

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The various post processing charts help us

understand the physics of the problem.

In this sense the design space charts are

valuable decision making tools.

The various charts depict the full design space,

the history of the optimization an its progress

towards the optimal solution

Optimization using mF allows Robust Design

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mF - Design Spacepost processing charts

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Specification

Optimization Goal

50ohm

FhighFlow Fcenter

Before OptimizationReturn Loss and VSWR Performance

Missiles & NCW DivisionR & D and Engineering

Directorate

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Specification

Optimization Goal

FhighFlow Fcenter

50ohm

After OptimizationReturn Loss and VSWR Performance

Missiles & NCW DivisionR & D and Engineering

Directorate

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Summary and Results

The Return loss and VSWR performance

were highly improved using the optimization

process.

34% bandwidth was obtained!!

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Thank You

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