Topic1 Introduction

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Topic 1 Introduction

1.1 Objective

The purpose of this topic is to familiarise you with the basics of Agilent ADS, which is the computer aided design tool to be used for this short course.

1.2 Starting ADS

Step 1: log in

Step 2: select program - server - ***

Step 3: Type /vol/ee/teach/HPads/2005a/bin/ads to start ADS2005.

Step 4: The first time you launch the application, you are prompted to choose which type of components you want loaded on start-up: Analog/RF Only, Digital Signal Processing only, or Both .Choose Analog/RF only for this course.

Step 5: When you dismiss the setup box, the ADS main window appears. The main window enablesyou to create and manage projects.

Step 6: Choose File > New Project and give a name to your project.

Simulation dataMomentum Designs & DataDesigns Schematics & LayoutsDSP Synthesis DataDesign Rule Checker Data


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Introduction - Creating Designs

Step 7: By default, a Schematic window is automatically displayed when you create a project.

Otherwise, choose Window > New Schematic to open a Schematic window.

Schematic Window is the window where you can create and modify your circuit.

1.3 Creating Designs

The basic process of creating a design is:

This section gives details of creating a design. These are essential skills in using ADS. It is stronglysuggested you practice as many as possible to get yourself familiar with various commands.

1.3.1 Placing a component

Step 1: Choose the component type. From the drop-down component Palette List select the componenttype you want. For example, select Tlines-Microstrip . Microstrip components appear in theComponent Palette on the left side of the schematic window.

Step 2: From the component palette, click to select MLIN (microstrip line), move the pointer into the drawing area, and click to place the symbol in the desired location. Click to return to select mode.

Placecomponent

EditParameters

ConnectComponents

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1.3.2 Editing Component Parameters

Once a component symbol has been placed in the drawing area, you can double-click it to display thedialog box for editing (or choose Edit > Component > Edit Component Parameter s).

Step 1: Select the parameter you want to change

Step 2: Change the parameter value as needed, and press Ente r. The Parameters list box is updated toreflect the new value.

Step 3: Click Apply to update and accept the new parameters.

Step 4: Click OK to dismiss the dialogue box.

Component Palette List

ComponentPalette

CancelCommand andReturn toSelect Mode

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1.3.3 Moving Components

You may also want to move the component to a new, desired location after you have placed it in thedrawing area. The quickest way to move components is with the mouse:

Step 1: Position the pointer over the component you want to move.

Step 2: Press the left mouse button, drag to the new location, and release.

1.3.4 Rotating Components

To rotate a component, from the Menu Bar, select Edit - Rotate , then click the component, or from theTool Bars, select rotate button , and click the component you want.

1.3.5 Connecting Components

You can connect components directly by placing one pin on top of another or you can connect themwith wires.To connect components with a simple wire:

Step 1: Click the Add Wire button.

Step 2: Position the pointer on the pin at one end and click.

Step 3: Position the pointer on the pin at the other end and click. A wire is drawn between thespecified points.

1.3.6 Zooming In and Out.

When working with a large design, you may need to zoom in on a particular part of the design, andthen zoom back out. There are several View menu commands for zooming in, but one of the mostfrequently used is the Zoom Area command. Zoom Area allows you to specify your own view windowfor zooming.

To specify a particular portion of the view for zooming:

Step 1: Choose Zoom Are a . You are prompted to enter the first corner.

Step 2: Move the pointer to the position representing one corner of the desired view window and click left. You are prompted to enter the second corner. As you move the pointer, a box drawn with a dashedline appears. This box represents the portion of the current view that will become the new view.

Step 3: Click left to specify the opposite corner of the desired view window. The specified portion of the design is magnified.

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Step 4: To redisplay the entire design:

Choose View Al l . Your design is scaled as needed and repositioned to fit it all in.

The other useful command includes:: Zoom in to designated point

: Zoom in by 2

: Zoom out by 2

1.4 LineCalc

LineCalc is an analysis and synthesis program integrated in ADS for calculating electrical and physicalparameters of single, and coupled, transmission lines. This is an essential tool for microwave circuitdesigners.

Step 1: Starting LineCalc. From the Schematic, choose Tools > LineCalc > Start LineCal c. TheLinCalc Window appears:

Step 2: In the Component Type field, click Select to display the component list. Select desiredcomponent and click OK. Two components used in this course are:

MLIN: Microstrip Line

MCLIN: Microstrip Coupled Line

Step 3: Inputing substrate parameters:

Er = relative dielectric constantMur = relative permeabilityH = substrate thickness, in specified unitsCond = conductor conductivity, in Siemen/meter Hu = cover height, in specified unitsT = conductor thickness, in specified unitsTanD = dielectric loss tangentRough = conductor surface roughness, in specified units

Step 4: Inputing Frequency parameter:

Freq: frequency of operation in specified units

Step 5: Inputing Electrical parameters:

Z0 : Characterstic impedance of microstrip lineOR

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ZE : even mode characteristic impedanceZO : odd mode characteristic impedanceE_Eff : electrical length

Step 6: click Synthesis to obtain physical parameters from the specified electrical data

Note: You can also enter physical data and click Analysis to obtain the correspondingelectrical data

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Topic1 Introduction