low noise amps

8/3/2019 Low Noise Amps

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Low Noise Amplifiers

EERF6395

RF/Microwave Systems Engineering

Dr. R. E. Lehmann


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Applications Receivers

Communications

Radio

Cell phone

WLANs, Bluetooth

Radar militar commercial

Narrowband Complements the transmitter as a T/R function

Electronic warfare

Wideband receivers

Channelized receivers Radio astronomy

Cryogenically cooled receivers

Very narrow bandwidths


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Inside a Cell Phone

Source: http://electronics.howstuffworks.com/inside-cell-phone.htm


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Transmit/Receive Module(T/R Module)

Driver Amp Power Amp

Phase

Shifter

LNA LimiterSwitch

Antenna

Circulator

Tx

Rx


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X-band T/R Module

Source: http://www.microwaves101.com/encyclopedia/transmitreceivemodules.cfm


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Radio Astronomy

The Goldstone Radio Telescope:

Located at the Goldstone Deep Space

Communications Complex in the Mojave Desert,

near Barstow, California.

diameter, is nine stories high, and weighs 850,000pounds.

Known as Deep Space Station 12 (DSS-12), the

antenna was used by NASA's Deep Space

Network to track robotic planetary missions such

as the Mariner missions, Voyagers 1 and 2,Galileo, and other spacecraft exploring the Solar

System.

Source: http://deepspace.jpl.nasa.gov/dsn/gavrt/index.html


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Arecibo ObservatoryThe Arecibo Radio Telescope:

Located in Arecibo, Puerto Rico

Its position near the equator allows viewing of

all the planets in our solar system

Diameter = 305m (1000 ft)

s e arges s ng e re ec or e escope n e

world.

Spherical reflector (not parabolic) to reduce

astigmatism when the receiver is in different

positions off the focal point. (The error of a

spherical reflector is the same in every

direction.)

Can transmit EIRP of 20TW at 2.38 GHz

Source: http://en.wikipedia.org/wiki/Arecibo_Observatory


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Univ. of Illinois Radio Telescope

Source: http://www.ece.illinois.edu/about/history/reminiscence/400ft.html

Professor H. D. Webb used this telescope from 1959-1969 to map a large portion

of the Milky Way galaxy.


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Cryogenically Cooled Receivers

Receivers are cooled to ~15K using liquid

helium

Special considerations must be given to

low temperatures.

Special packaging and assembly must be

considered to prevent damage due to thelarge temperature change.


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Low Noise Device Technology Semiconductor material

Silicon (Si) Silicon Germanium (SiGe)

Gallium Arsenide (GaAs)

Indium Phos hide InP

Devices Field Effect Transistor (FET)

Bipolar Junction Transistor (BJT)

Heterojunction Bipolar Transistor (HBT)

High Electron Mobility Transistor (HEMT) Pseudomorphic HEMT (pHEMT)

Metamorphic HEMT (mHEMT)


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Low Noise AmplifierSimplified Single-ended Design

Input

Matching

Network

Interstage

Matching

Network

Output

Matching

Network

S S * SS S * S S *

First stage is designed for minimum noise figure.

Input matching network is designed to present the optimum noise match, opt,

to the first stage transistor.

Note: opt is NOT = to S11*

Second stage is designed for a combination of:a) Maximum gain

b) Maximum output return loss

c) Flat gain response across frequency

d) Maximum TOI


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Balanced Amplifier

Input 50- Load

Output50- Load

3-dB

Coupler

3-dB

Coupler

Advantages:

Excellent I/O return loss

Approx. 3dB more Pout & OIP3

Less sensitivity to source & load

Disadvantages:

Large size compared to single-ended

Twice as much DC power required

Higher cost


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Balanced LNA NF

Input 50- Load

Output50- Load

3-dB

Coupler

3-dB

Coupler

Gain (dB) -0.5 20 -0.5

F (dB) 0.5 1.5 0.5

Po (dBm) 13 15.5

OIP3 (dBm) 23 25.5


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Balanced NF Calculation For balanced noise figure calculations, the

balanced topology can be treated as asingle-ended cascade:

Input

Coupler

Output

Coupler

Gain (dB) -0.5 20 -0.5

F (dB) 0.5 1.5 0.5


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Balanced NF Calculation

GG

F

G

F

FFtot

)112.1()141.1(

)1()1(

21

3

1

2

1

+

+=

dBF

F

F

tot

tot

tot

tot

0.258.1

0013.046.012.1

)100)(89.0(89.0.

=

=

++=


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LNA Biasing+V

(drain supply)

+V

(drain supply)

-V

(gate supply)

Dual-bias configuration:

More precise bias conditions

Easier to adjust for optimal performance Requires two independent supplies

Self-bias configuration:

Single supply

Often difficult to adjust current Lower cost to implement in system


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http://www.triquint.com/prodserv/more_info/proddisp.aspx?prod_id=TGA2511


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TriQuint TGA2511 LNA



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TGA2511 LNA Specifications

(Dual-supply bias)

Parameter Typical Worst Case Units

Frequency range 6 14 6 - 14 GHz

Drain voltage, Vd 5.0 5.0 V

Drain current, Id 160 160 mA

Small-signal gain, S21 20 19 dB

Input return loss, S11 18 16 dB

Output return loss, S22 18 14 dB

Noise figure 1.3 1.7 dB

Output power @ 1dB comp., P1dB 12 10 dBm

OIP3 (TOI ref. to output) 24 21 dBm

[Source: www.triquint.com]


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TGA2511 LNA

Gain Performance



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TGA2511 LNA

Noise Figure Performance



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TGA2511 LNA

P1dB Performance



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TGA2511 LNA

OIP3 Performance



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Hittite HMC564LC4 LNA

GaAs pHEMT Low Noise Amplifier

Typical performance: Frequency range: 7-14 GHz

Noise Figure = 1.8 dB

Gain = 17 dB

Functional Diagram

= m

Single supply: 3V @ 51mA 50-ohm in/out

4x4 mm package

http://www.hittite.com/content/documents/data_sheet/hmc564lc4.pdf


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Hittite HMC564LC4 LNAParameter Typical Worst Case Units

Frequency range 7 14 7 - 14 GHz

Drain voltage, Vd 3.0 3.0 V

Drain current, Id 51 75 mA

Small-signal gain, S21 17 14 dB

Input return loss, S11 16 15 dB

Output return loss, S22 14 13 dB

Noise figure 1.8 2.2 dB

Output power @ 1dB comp., P1dB 13 10 dBm

OIP3 (TOI ref. to output) 25 25 dBm

[Source: www.hittite.com]


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Temperature Performance will vary over temperature

Variation must be comprehended in systemspecs over expected temp range

, ,

sensitive to temp variations

Gain ~ -0.01 dB/oC per stage

Ex: 2-stage LNA: G=2.5 dB for T=125C Noise Figure ~ +0.008 dB/oC

Ex: 2-stage LNA: F=1.0 dB for T=125C

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