optenni lab presentation - moasoft lab presentation.pdf · optenni lab presentation author: jra...

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Optenni Lab

Easy-to-use impedance matching tool for

antenna designers

Optenni Ltd, May 22, 2013


Optenni Lab • Optenni Lab is a fast and easy-to-use matching circuit

generation and antenna analysis tool tailored for

antenna designers

• Main features:

– Fast automatic matching circuit generation including a

component library and sensitivity analysis

– Simultaneous multiport matching

– Estimation of obtainable bandwidth of antennas at various

frequencies using the bandwidth potential technique

– Calculation of worst-case isolation for two-antenna

systems



MATCHING CIRCUIT

GENERATION

Main Features of Optenni Lab



Traditional matching circuit generation

1. Using a circuit simulator, guess a suitable matching

circuit topology and give initial values for the

components

2. Set up frequency markers manually

3. Try to tune the circuit values by hand

4. Try to use the optimization features of the circuit

simulators

5. If the results are not good, start again and try

another topology



Problems with the traditional method

• Circuit simulator skills needed

• Theoretical impedance matching knowledge needed

to select the matching circuit topologies

• Difficult to choose a correct topology for

multiresonant cases

• Optimization routines are difficult to use

– Setting frequency ranges is tedious

– Optimization criteria might not be the best ones

• Whole process takes many laborious iterations and

possibly hours



Optenni Lab: Matching circuit generation 1. Select antenna impedance file

(multiport S parameters from a Touchstone file)

2. Select termination impedances

3. Select frequency ranges

4. Select number of components in matching circuits

5. Click OK

• Whole procedure takes less than 30 seconds

• No impedance matching or circuit simulation skills needed



Results of matching circuit generation


All previous results available

in a project tree

S parameters (S11, S21) through

the matching circuit

S11 on the

Smith chart

Generated

circuit

Multiple

topologies

generated

Circuit

performance


Component library

• Optenni Lab includes a library of

commonly used inductors and

capacitors

• Initially almost 30 component series

from three major manufacturers are

supported and more are planned

• The optimization using components

from the library is fast and easy

• Component library is also compatible

with sensitivity analysis



Sensitivity analysis

• The sensitivity of the results with

respect to component

tolerances can be analyzed for

both the generic component

models and the library models.

• Also yield and minimum

efficiency is calculated

• The sensitivity analysis only takes

a few seconds



Optimization of efficiency

• For matching circuits with lossy matching

components, Optenni Lab is optimizing for S21,

which is equivalent to the total efficiency of the

matching circuit (including both impedance mismatch

losses and thermal losses in the matching circuit

components)

• Optimization of the impedance match alone would

lead to suboptimal total efficiency

• In many other programs it is difficult to optimize for

the total efficiency (S21).



Options in matching circuit generation

• Manually given topologies

• Losses in matching circuit

components: S21 of circuit

optimized, component

losses calculated

• Fixed component values

• Limits for component

values

• Interactive tuning of

generated circuits



Impedance trace • Impedance trace shows how

the components change the

impedance on the Smith chart

at the visualization frequency

• Very useful feature for

understanding the operation of

the matching circuit

• Can be combined with

component tuning and

interactive selection of the

visualization frequency


Effect of series capacitor

Effect of shunt inductor


SIMULTANEOUS MULTIPORT

MATCHING




Main features

• Simultaneous multiport matching compatible

with automatic topology creation,

component library, tolerance analysis etc.

• For antenna applications: optimization of

efficiency

• For filters or amplifiers: optimization of S21

etc.

• Arbitrary number of ports

• Termination of ports (internal ports for

single components)



Multiport antenna matching

• Not enough to have good matching (e.g. both |S11|2

and |S22|2 small)

• Not enough to have good matching and isolation

(|S11|2 , |S21|

2 and |S22|2 small)

• Need to consider antenna total efficiency, taking into

account matching circuit losses and coupling to other

ports



Multiport antenna matching

• Easy to use: just click on

the ports to set the

frequency ranges and the

circuits to set number of

components or topology

• Multiple topologies

optimized for each port

• Fast parallel optimization



Output data

• Circuit topology

• Efficiencies

• S parameters



Additional options

• Ports can be terminated using a

single component (e.g. internal

ports in EM simulations used

for component placement)

• Specifications for efficiency stop

bands and isolation



General multiport matching

• Applications: amplifiers, filters, switches, coupled coils

etc.

• Typical figure of merit: |S21|2 to be large in passband

and small in stopband

• Maximum possible |S21|2 given by the concept of

electromagnetic isolation

• Targets: pass and stop bands for Sij



ESTIMATION OF

OBTAINABLE BANDWIDTH:

BANDWIDTH POTENTIAL




Estimation of obtainable bandwidth • The obtainable bandwidth

of an antenna through a

two-component matching

circuit can be quickly

estimated using the

bandwidth potential

technique

• The analysis makes it easy

to compare antenna

prototypes (without

matching them explicitly)



Benefits of bandwidth potential

• Quikcly shows the obtainable bandwidth of a

prototype without explicit tuning

• Differently matched antennas can be compared

• Can be used to select the best antenna candidate

• Shows at which frequency the best bandwidth is

obtained

• Can be used to verify the antenna operation: best

bandwidth should be obtained at the operation

frequency bands



Example of bandwidth potential usage

• Ground plane: 40 mm by 100 mm

• Patch: 25 by 20 mm, height 5 mm


Case 1 Case 2: 19 mm by 14 mm removed


Impedances of example antennas


Based on original unmatched

impedances it is difficult to

say which antenna is more

wideband and how large

bandwidth could be

obtained.


Bandwidth potential results


Case 1 Case 2

Bandwidth potential calculation

shows that antenna 1 is more

wideband at the lower operating

frequency but antenna 2 is more

wideband at the upper

frequencies (although the antenna

is smaller).


Bandwidth potential and parameter sweeps Height of antenna 2 varied


Difficult to see the effect of the

height. Seems to lower the upper

resonance frequency?

The maximum bandwidth of the

upper resonance stays at the

same frequency, lower resonance

becomes more wideband.

Raw impedance data Bandwidth potential


Summary of bandwidth potential

• Using raw impedance data it is difficult to compare

differently matched antennas and it is difficult to see

how large bandwidth could be obtained with

impedance tuning.

• Bandwidth potential calculations show the obtainable

bandwidth at all frequencies, making comparison of

different antennas easy. Bandwidth potential can also

be used with parameter sweeps.

• Bandwidth potential saves antenna design time and

reduces the number of prototypes.



CALCULATION OF WORST-

CASE ISOLATION




Calculation of electromagnetic isolation • Electromagnetic isolation is the worst case isolation at each

frequency when two ports are simultaneously conjugate

matched at that frequency.

• It can be used to compare different antenna systems (e.g. in

diversity applications) in terms of their isolation

characteristics without matching the ports manually.


S21

Electromagnetic isolation


Usage of electromagnetic isolation

• Electromagnetic isolation can be used to select best

position for diversity antennas.

• Moving the diversity antenna will change the

matching of diversity and main antennas and thus

also the antenna isolation. Observed isolation might

be large only due to poor matching.

• Electromagnetic isolation shows how the isolation

changes in the case that both antennas would be

matched and can thus be used to reliably compare

the isolation in different positions.



OTHER FEATURES AND

SUMMARY

Optenni Lab



Additional features

• Generation of matching circuits that obtain conjugate

matching to the termination impedance or maximize

the bandwidth around a starting frequency

• Calculation of radiation efficiency from impedance

and total efficiency data with different frequency

grids

• Capability to read and write project files containing

the previously computed results

• Comparison of different results on the same plot

• On-line manual



Link between CST and Optenni Lab

• A two-way link between

Optenni Lab and CST

STUDIO SUITE™ has been

developed

• Optenni Lab can be launched

from within CST

• Matching circuits generated

in Optenni Lab can be

transferred to CST DESIGN

STUDIO™ for further

analysis



Advantages of using Optenni Lab • Fast matching circuit generation

• Rapid estimation of obtainable bandwidth

• Easy comparison and evaluation of antenna

prototypes

• Optimal total antenna performance obtained

• Very intuitive graphical user interface

• Can be easily operated also by nonspecialists

• Developed further based on user feedback

• Optenni Lab increases the productivity of antenna

designers and reduces the design times of antennas


optenni lab presentation - moasoft lab presentation.pdf · optenni lab presentation author: jra...

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