communication electronics research...

Communication Electronics Research Group

www.comelec.itn.liu.se

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Multiport Technology

Guiding and superposition of RF signals

In a passive component

Wave interference

Introduction

The multiport network acts as an interferometer

It guides high frequency signals (waves) through different paths so that they are superimposed

The signals interfere

The result is a “pattern” from which information about the signals can be extracted

Optical interferometry is an traditional laboratory technique used for accurate measurements

The “electrical” interferometer relies on the fact that signals at GHz-frequencies have so small wavelengths, that small path differences results in measurable phase and

amplitude differences



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Multiport Technology

Microwave Passive Components

The multiport network consists of microwave passive components based on quarter-wave (λ/4) transmission lines

Example above: Quadrature coupler

Design aspects:

Designed for operation frequency, f0

They can be improved in terms of larger bandwidth

Are characterized by small deviations against theoretical phase- and amplitude-expected values

The occupied area is inversely proportional with operation frequency, f0

Quadrature coupler Wilkinson power divider

V+·ejωt

αV+·ej(ωt-90°)

αV+·ej(ωt-180°)



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Multiport Technology Applications

1970’s: Accurate measurements of the complex reflection coefficients

1994: Microwave and millimeter wave radio receivers

Today:

Network analysis: Reflection coefficients, phase and frequency analysis

Data transmission: Direct modulation/demodulation at RF/MW frequencies with low-power and low-costs

Radar, automotive: Distance and angle-of-arrival measurements

Radar, medical: Heartbeat and respiration rate measurements Automotive and medical

radar applications

Low-power, broadband communication systems

Multi-port Multi-port



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Research at Comelec

4 2

LO

b5

Zo

a6

Z4 Z2

Z1 Z3

6

5

1 3

H 90

H 90

H 90

Zo

2

6aj

2

6a

631

22

ΓΓaj

642

22

ΓΓa

W

4 2

1 3

l

Q

16-QAM constellation diagram

of the RF modulated signal



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Research at Comelec

Radio receiver – Multiport demodulator implementation

The local oscillator (LO) is connected at port 5

The received RF signal is amplified by the low-noise amplifier (LNA) and applied at port 6.

Square-low matched power detectors are connected to the output ports 1 to 4 of the circuit. The output signals are linear phase shifted combination of inputs

Two differential amplifiers are used to obtain the quadrature I- and Q-signals

The circuit can operated either in direct conversion or low intermediate frequency (IF) schemes

b4

LOa5

Zo

a6

6

5

1 3

4 2

+

-I

-

+

Q

b3

b1

b2

H 90

H 90

H 90

W

LNA



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Research at Comelec

Pros of the Multiport Technology

The main advantage is the reduced LO

power to operate in both Tx- and Rx-mode

Broadband operation, hence high data rate

High linearity

Very accurate phase difference detector

Integrability with other high performance RF components

Low-cost

Short time from design to prototype

6 14

5 32

Multiport modulator

with ROGER 4350B Constellation of the RF signal

400 Mbit/s 1.2 Gbit/s

Cons of the Multiport Technology

Relatively low-sensitivity

Large dimensions at lower frequencies

Multiport technology is a flexible but unitary RF/MW technology for:

High-data rate data transmission with low-power consumption

Network analysis

Localization purposes

Distance measurements

Angle-of-arrival (AoA) measurements

Vibration analysis based on ultra-high resolution measurements (one-digit

micrometer or nanometer range)

Contact person: Adriana Serban

› [email protected]



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Sensors, actuators, RFID, robots……

Internet(HTTP, E-mail…)

Internet of Things

Wireless technologies:3G/4G, WiFi, Bluetooth,ZigBee, 6-LoWPAN…

Wireless sensor networks

Wireless InternetWeb of Things



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Around 30 deployment sites and 11 sensors + radio transmitters per site

Vasa museum

Linköping Cathedral

Swimming house in Norrköping

University Hospital in Uppsala

Heritage house on Gotland

……………………



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Wirelesss sensor networks

Kit 3 Kit 2

Kit 1

Kit 4



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Sensor/Tag-1

Routers

R2

R1

R3

R4

R5

R6

Reader

User

Sensor/Tag-2

Radio

R3

World-leading IOT technology with cloud service

Proven in the Church/Museum and Hospital environments

Flexible for third-party cooperation

Long radio range with mesh network

Low power consumption (10 year battery lifetime with 15-min sampling interval)

Secure solution with encryption (AES128)

Robust system: measured data is saved in sensor modules first and then

forwarded to the local server and finally the web server

Low cost

Contact person: Shaofang Gong, [email protected]

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