Passive Technology Presentation
Transcript of Passive Technology Presentation
-
8/8/2019 Passive Technology Presentation
1/36
www.BesserAssociates.com
Besser Associates, Inc.
Passive Component
Technology
Bob Froelich, Besser Associates
Sponsored byRes-net Microwave, Inc.
Wavetronix Corp.
-
8/8/2019 Passive Technology Presentation
2/36
www.BesserAssociates.com
Besser Associates, Inc.
In business for over 25 years
Leading supplier of passive components
to 26.5 GHz
Custom & standard parts available
ISO 9001:2000 certified
www.res-netmicrowave.com
Res-net Microwave, Inc.At a Glance
Thinking at a Higher Frequency
-
8/8/2019 Passive Technology Presentation
3/36
www.BesserAssociates.com
Besser Associates, Inc.
Microwave Resistors & Terminations
DC to 26.5 GHz
Coaxial, Flange, & Rod
Available in AlN & BeO
www.res-netmicrowave.com
Res-net Microwave, Inc.
-
8/8/2019 Passive Technology Presentation
4/36
www.BesserAssociates.com
Besser Associates, Inc.
Microwave Attenuators
DC to 26.5 GHz up to 2,000 watts
Coaxial & Flange
Available in AlN & BeO
www.res-netmicrowave.com
Res-net Microwave, Inc.
-
8/8/2019 Passive Technology Presentation
5/36
-
8/8/2019 Passive Technology Presentation
6/36
www.BesserAssociates.com
Besser Associates, Inc.
MIL-C-17U
Low loss cable
0.034 to .250 diameters
Custom assemblies available
Typical VSRW 1.2:1 @ 18GHz
Wavetronix Corp
www.wavetronix-eti.com
-
8/8/2019 Passive Technology Presentation
7/36
www.BesserAssociates.com
Besser Associates, Inc.
Passive Component
Technology
Dr. Bob Froelich
Senior Principal Engineer
Cobham
-
8/8/2019 Passive Technology Presentation
8/36
www.BesserAssociates.com
Besser Associates, Inc.
The Ideal Elements
Element Principle Relation Impedance
Ohms
Law
V = IR R
Faradays
LawV = L dI/dt jL
Gauss Law I = C dV/dt 1/jC
-
8/8/2019 Passive Technology Presentation
9/36
www.BesserAssociates.com
Besser Associates, Inc.
Real Elements
Are never ideal
Can often be modeled as a simpleequivalent circuit of ideal elements
Come in many physical forms, dependingon Cost
Frequency Power Levels
Etc.
-
8/8/2019 Passive Technology Presentation
10/36
www.BesserAssociates.com
Besser Associates, Inc.
Some Surface Mount Sizes
W
L
Metric LxW(mm)
US LxW(mils)
0603
(= 0.6 x 0.3)
0201
(= 24 x 12)1005
(= 1 x 0.5)
0402
(= 40 x 20)
1608 0603
2012 0805
3216 1206
-
8/8/2019 Passive Technology Presentation
11/36
www.BesserAssociates.com
Besser Associates, Inc.
Models and Parasitic Elements
An ideal element of the type desired is usuallythe main feature of the model network.
The other elements in the model are often called
parasitic elements. How parasitics arise Energy loss (as heat) => resistance
Physical area => capacitance
Physical length => inductance All elements in the model can vary with
frequency and temperature.
-
8/8/2019 Passive Technology Presentation
12/36
www.BesserAssociates.com
Besser Associates, Inc.
Lumped vs. Distributed
Lumped element:
Small compared to the wavelength of the highestfrequency which is significant.
Can be treated (electrically) as having zero size. Distributed element:
Not small compared to wavelength. (>~ / 10)
Voltage or current phase differs from one side to the
other due to distance.
Model must include transmission line or manyincremental lumped elements.
-
8/8/2019 Passive Technology Presentation
13/36
www.BesserAssociates.com
Besser Associates, Inc.
Inductors
In HF/RF/Microwave circuits, inductors aremainly used for RF blocking element to feed DC power or
connect DC ground. (RF chokes) Impedance matching.
Manufacturers often furnish equivalentcircuit model or S-parameters.
Many forms, but all include a conductingspiral that couples to a magnetic field.
-
8/8/2019 Passive Technology Presentation
14/36
www.BesserAssociates.com
Besser Associates, Inc.
Some RF/Microwave Inductors
Wire on ceramic
Laminated Spiral
Wire onFerrite Toroid
Conical
-
8/8/2019 Passive Technology Presentation
15/36
-
8/8/2019 Passive Technology Presentation
16/36
www.BesserAssociates.com
Besser Associates, Inc.
Primary Inductor Properties
Inductance: Primary function of the part
Self Resonance: As some frequency thereis a parallel resonance between the
inductor the parasitic capacitor. Quality factor (Q): characterizes the loss
Defined as Im(Z) / Re(Z)
Differs from the Q definition used forresonators:
2(peak stored energy)/(energy loss in 1 cycle)
-
8/8/2019 Passive Technology Presentation
17/36
www.BesserAssociates.com
Besser Associates, Inc.
Modeled Inductor Reactance and Q
0.2 0.4 0.6 0.8 1.0 1.2 1.40.0 1.6
-2000
0
2000
-4000
4000
5
10
15
0
20
freq, GHz
Reactance
,Ohms
Q
-
8/8/2019 Passive Technology Presentation
18/36
www.BesserAssociates.com
Besser Associates, Inc.
Some Inductor Types
Different cores Air: lowest loss and lowest C Ceramic: close to air, better structure Ferrite: more L in a small space. Can be lossy and
frequency-dependent. Different windings
Wire: low loss Printed/laminated windings: low cost / low Q
Planar Spiral Used in RFICs Usually have poor performance: low Q and high C.
-
8/8/2019 Passive Technology Presentation
19/36
www.BesserAssociates.com
Besser Associates, Inc.
82 uH Multilayer Inductor
Black: Simplemodel with 1.4pFparallel
capacitance
Blue: Measuredresponse
0 1.0
1.0
-1.0
10.0
10.0
-10.0
5.0
-5.0
2.0
2.0
-2.
0
3.0
-3.
0
4.0
-4.0
0.2
0.2
-0.2
0.4
0.
4
-0
.4
0.6
0.
6
-0
.6
0.8
0.
8
-0
.8
Reflection CoefficientSwp Max
3000MHz
Swp Min
0.1MHz
814 MHzr=0.644
x=-3.1e-3
Measured
Modeled
5.0
x=-1003.
0
4.0
r=12.115 MHz
5.0
x=-1003.
0
4.0
r=12.13.0
4.0
r=12.115 MHz
-
8/8/2019 Passive Technology Presentation
20/36
www.BesserAssociates.com
Besser Associates, Inc.
Using Inductors
RF choke Goal is high reactance with low resistance
OK to use an inductor at self-resonance
Impedance matching
Goal is accurate reactance and (usually) low resistance Usually must stay well below self-resonance
Some things to look for Tolerance and SRF
Q
Current handling
Try to use the lowest L that can do the job.
-
8/8/2019 Passive Technology Presentation
21/36
www.BesserAssociates.com
Besser Associates, Inc.
Capacitors
In HF/RF/Microwave circuits, capacitors aremainly used for
DC blocking to isolate bias or create an RF ground
(RF bypass) Impedance matching
Manufacturers often furnish a circuit model or S-parameters
Possibly the most complicated passive due toeffects of structure, temperature, materials, etc.
-
8/8/2019 Passive Technology Presentation
22/36
www.BesserAssociates.com
Besser Associates, Inc.
Multilayer Capacitor Structure
-
8/8/2019 Passive Technology Presentation
23/36
www.BesserAssociates.comBesser Associates, Inc.
Example of Capacitor Model
Model approximates thereal capacitor from DCto above first self-resonance.
Parasitic elements are Loss: Contact and plate
resistance, plus loss indielectric
Inductance: Current flowsets up magnetic field
0.3nH 0.07
36k
27pF
27pF, 0402 SMT Capacitor
-
8/8/2019 Passive Technology Presentation
24/36
www.BesserAssociates.comBesser Associates, Inc.
Primary Capacitor Properties
Capacitance: Primary function of the part
Self-resonance: At some frequency there is aseries resonance between the capacitor and the
parasitic inductance. Quality factor Defined the same as for an inductor
RF/Microwave capacitors often have higher Q than
inductors. Other
Breakdown voltage
-
8/8/2019 Passive Technology Presentation
25/36
www.BesserAssociates.comBesser Associates, Inc.
Modeled Capacitor Susceptance
and Q
0.5 1.0 1.5 2.00.0 2.5
0
-1
1
Susceptan
ce,mhos
0.5 1.0 1.5 2.00.0 2.5
-5
0
5
-10
10
100
200
300
0
400
freq, GHz
Susceptance,mhos
Q
-
8/8/2019 Passive Technology Presentation
26/36
www.BesserAssociates.comBesser Associates, Inc.
Some Capacitor Types
Plate Configuration
Multi-layer is an encapsulated stack of metal plates.
Single-layer is just two plates; used with chip-and-
wire Dielectric (Insulator) Material
Ceramic: many kinds
Oxide (i.e. MOS capacitor): primarily single-layer
Electrolytic and tantalum capacitors are seldomused at high frequencies.
-
8/8/2019 Passive Technology Presentation
27/36
www.BesserAssociates.comBesser Associates, Inc.
Dielectric Materials
Ceramics Most common material
Ceramics with high dielectric constant () deliver morecapacitance in a small package.
High- ceramics are temperature- and voltage-dependent, andthey are often more lossy than low- materials.
Oxide Very temperature stable
Producible in thin layers for high capacitance
Thin layers result in low breakdown voltage Used mainly in single-layer capacitors.
Categories for ceramics have been defined by theElectronic Industries Alliance
-
8/8/2019 Passive Technology Presentation
28/36
-
8/8/2019 Passive Technology Presentation
29/36
www.BesserAssociates.comBesser Associates, Inc.
Other Dielectric Properties
Materialtype
r at roomtemperature, typ.
Dissipation factor, % ofenergy converted to heat
(low frequency), typ.
Change withvoltage (0V to rated
voltage), typ.
SiO2 3.9 < 0.1 ~ 0
NPO 60 0.1 ~ 0
X7R 3500 3.5 -50%
Y5V >16000 9 -90%
-
8/8/2019 Passive Technology Presentation
30/36
www.BesserAssociates.comBesser Associates, Inc.
Using Capacitors
DC block or RF bypass: Requires high susceptance OK to use a capacitor near self-resonance
Impedance matching Requires accurate susceptance Usually must be well below self-resonance
Watch out for Temperature sensitivity
Tolerance and SRF Breakdown voltage
Try to use the lowest C than can do the job.
-
8/8/2019 Passive Technology Presentation
31/36
www.BesserAssociates.comBesser Associates, Inc.
Resistors
In HF/RF/Microwave circuits, resistors are
used mainly for
Attenuators
Terminations
Feedback
Manufacturers sometimes furnish model or
S-parameters.
-
8/8/2019 Passive Technology Presentation
32/36
www.BesserAssociates.comBesser Associates, Inc.
Example of Resistor Model
Model approximatesthe real resistor fromdc to about 6GHz.
Parasitic elementsare
Inductance: due tolength
Capacitance: due tocontact area
50 0.17nH
0.08pF0.08pF
50 0603 SMT Resistor
-
8/8/2019 Passive Technology Presentation
33/36
www.BesserAssociates.comBesser Associates, Inc.
Modeled Resistor Impedance
2 3 4 5 6 71 8
51
52
53
54
55
50
56
1
2
3
4
5
6
0
7
freq, GHz
Resistance,
Ohms
Reactance,Ohms
-
8/8/2019 Passive Technology Presentation
34/36
www.BesserAssociates.comBesser Associates, Inc.
Other Resistive Forms for
RF/Microwave
Attenuator (coaxial orsurface mount)
Fixed
Temperature-dependent
Termination
High power (with heat
sink) Small/high frequency
-
8/8/2019 Passive Technology Presentation
35/36
www.BesserAssociates.comBesser Associates, Inc.
Watch Out For
Leaded resistors (or capacitors, inductors)
Leads add series inductance and/or length
Wire-wound, carbon film and MELFcylindrical resistors
Resistive element is often in the form of aspiral. At RF it becomes a lossy inductor.
1/F noise: Some resistor types generatemore than others.
-
8/8/2019 Passive Technology Presentation
36/36
www BesserAssociates com
Passive Component
TechnologyBob Froelich, Besser Associates
Sponsored byRes-net Microwave, Inc., www.res-netmicrowave.com
Wavetronix Corp., www.wavetronix-eti.com