Xiaoyu Cheng

Advisor: Dr.Yong-Kyu Yoon

Agenda HFSS Fundamentals

Case Study:

Transmission line

Basic SRR Antenna

Waveguide Loaded with SRR

Advanced Features

Q&A

HFSS: What’s this? High Frequency Structure Simulator

3D Simulator using FEM (Finite Element Method)

HFSS: How Accurate? HFSS v.s. Agilent E5071C after calibration

5 6 7 8 9 10 11 12-50

-40

-30

-20

-10

0

Frequency (GHz)

S1

1 a

nd

S2

1 (

dB

)

S11 Sim

S21 Sim

S11 Meas

S21 Meas

HFSS: Interface

Project Manager

Variables

Message Progress

3D Modeler

HFSS: First Thing First Solution Type Setup (HFSS>>Solution Type)

S-Parameter based on Power; for Microstrips, waveguides, (non-TEM modes) Higher modes in WG

S-Parameter based on V, I ; for multipiece conductor such As CPW, CBCPW, coaxial(TEM modes)

Eigenmodes, or resonances, of a structure.

Time Domain Response

HFSS: Before Your Drawing What’s the blank area?

They are PERFECT CONDUCTORS!(NOT AIR)

Most of the cases, you need an air box enclosing your circuit

HFSS: Your Model Most tools are easy to handle

Equation based surfaces, helix and coils are tricky. (Understand the meaning of rotating along the vector)

HFSS: Drawing Make your model “as central as possible”: Symmetric

will ease your drawing using rotation and duplication function

Use variable as much as you can(optimization)

HFSS: Drawing Make sure you have “Air-box” around your structure

(Why? -> P7)

Air box should be at LEAST as large as quarter wavelength of your lowest frequency of interest

Air boxes with unnecessary large volume will increase your simulation time.

Usually you need “Radiation” boundary on each side of the air box

HFSS: Excitation Wave Port: Stays ON the air box; has “Deembed”

function, ideal for Waveguide, microstrip

Lumped port: Embedded on the structure, for CPW/ CBCPW

HFSS: Waveport If you are using Driven Terminal: Choose your

reference conductor (GND)

If you are using Driven Model: Draw your “Integration line”: GND->Trace

HFSS: Lumped Port Similar with Waveport, but it does not necessarily stay

on the Air box

Only excite simplified single mode excitation, cannot perform deembed

HFSS: Port Size You are responsible to draw a 2D planar rectangular as

your port (except WG)

The standard recommendation for most CPW wave ports is a rectangular aperture

Port width should be no less than 3 x the overall CPW width, or 3 x (2g + w)

Port height should be no less than 4 x the dielectric height, or 4h

HFSS: Port Size Microstrip WavePort : at LEAST 5*TraceWidth

(Preferably 8x), 5*SubstrateThick (10x)

Run a “Port Only“ simulation to determine if the port size is correct (Quasi-TEM)

HFSS: Solution Setup Add a Setup

Solution Frequency: will be detailed later

Number of Passes: 10-20

Delta S: 0.02 (Default) <-> Accuracy

HFSS: Frequency Sweep Solution Frequency depends on Sweep type:

Fast: Narrow band application: Antenna

Discrete: Equivalent to discrete sweep on VNA

Good for broadband application

Interpolating: Do discrete computing on less number of points(such as 50), more number of points (401 or 801) will be interpolated based on the actually calculated points

HFSS: First Simulation If you are targeting very high performance system,

simulation of transmission line is suggested

Transmission line can be designed by TxLine (www.AWR.com), then a full wave FEM analysis is needed in HFSS for best results.

Case 1: Microstrip Line Design Substrate: Rogers RT/Duroid 5880 (k=2.2, thickness =

25mil, Half oz Cu coated, loss tan = 0.0009)

Wavelength

Trace Width

Case 1: Microstrip Line Design Create your model

Case 1: Microstrip Line Design When Symmetric: Two Ports

Case 1: Microstrip Line Design Before Frequency Sweep, run a “Solve Port Only”

analysis: Make sure port size is acceptable

Case 1: Microstrip Line Design E-Field is displayed; Quasi-TEM mode is observed as

the same on your textbook

Case 1: Microstrip Line Design

Case 1: Microstrip Line Design Before Plotting the results

Case 1: Microstrip Line Design

Case 1: Microstrip Line Design

Case 1: Microstrip Line Design

Case 1: Microstrip Line Design

Case 2: An SRR Antenna X. Cheng, D.E. Senior, J.J. Whalen and Y.K.Yoon,

“Electrically Small Tunable Split Ring Resonator Antenna ” IEEE Antenna and Propagation Symposium (AP-S) 2010, Jun.2010, Toronto, Canada, pp.1-4

Case 2: An SRR Antenna Microstrip: Driven Terminal, Waveport, Fast Sweep

Port Validation

Solution: Solution Freq. = Center Freq. (ANT) Fast Sweep

Case 2: An SRR Antenna # of adaptive passes : 30 (Huge!)

Case 2: An SRR Antenna

Dual Band! But why?

Case 2: An SRR Antenna Field Distribution

2.1GHz 3.8GHz

Case 2: An SRR Antenna 3D Radiation Pattern

Antenna Parameters

Case 3: Waveguide Loaded with SRR X.Cheng, J.Shi, P.Jao, D.E.Senior and Y.K. Yoon,

“Reconfigurable split ring resonator array loaded waveguide for insitu tuning” IEEE Antenna and Propagation Symposium (AP-S) 2011, Jul.2011, Spokane, WA, pp. 2947 - 2950

Case 3: Waveguide Loaded with SRR

Case 3: Waveguide Loaded with SRR

Case 3: Waveguide Loaded with SRR E-Field at 4GHz (TE10 mode, Transmission)

Case 3: Waveguide Loaded with SRR E-Field at 1.6GHz (Evanescent mode)

Case 3: Waveguide Loaded with SRR

Case 3: Waveguide Loaded with SRR

Case 3: Waveguide Loaded with SRR

Advanced Features Field Plotting

Select the plane which the 3D field will be projected on

Select the parameter of interest

Advanced Features Mesh Assignment (nano- and submicro structures)

Advanced Features Optimization (project properties) and tuning

Advanced Features Wrap sheet (HFSS 13.0 only)

Q&A

Multidisciplinary Nano and Microsystems Laboratory