Presenters:

Ohad Fremder031179245

Assaf Haim037653730

Projects Goal

To detect the presence of a working cellular device within a confined room.

To locate the cellular device within the confined space at a 0.5x0.5m accuracy.

Solution Steps Build pre unit. Build one full unit. One system builds from three units. Placed the systems is the room (four systems). Connect the systems to a computer.

Assumptions:

• There will be only one cellular device in the room, there will be no other RF in that room

General overview

We placed four systems with in the room (two on each side wall).

Each system consists of three basic units Every unit is built of a dipole isotropy

antenna, filters, gains, mixers, sum, energy detector.

Basic Unit

Basic Unit schema:

Filter

Bank of Filters

Mixers

Gains

Gains

E.D

sum

Pre Unit

In order to build the entire system we need to build a basic unit for a specific device.

H.Pass1.7Ghz

Antenna

L.Pass1.9Ghz 20db

L.O 1.5Ghz

Mixer

26db 26db

Energy Detector

L.Pass400Mhz

-1db -1db

-7db

-1db

20db

Pre system

The pre system is the key to solve the problem. We build the system wire up, therefore each component

will be on "Print" ready for connection. For testing purposes we use a VCO to simulate a cellular

device. The VCO and the mixer are the main components in the

system therefore we designed them in separately.

VCO And Mixer

Schema:

GND

IF

LO

RF

MixerSRA-220

V.C.OPOS-2000-3db

-3db

RFout

V-Tune

Vcc1

GND

1

3

2,5,6,7

8

2 8

3-7

VCO

Pin View:

150 250

POS-2000A

7 5 3

6 48

1

2

37.5 300

50

9inV V

2K

24inV V 4K

10 0pR K

1

2

1

0.1

C nF

C F

VCO

Operating DC voltage at 8V. To make sure that the power source is stable we used

capacitors. To protect the Mixer from returning signals we applied

3dB loss in its input, for that we designed a pie net resistors and placed it in the VCO output.

We need different values for Vtune so we use a 24V source with a potentiometer.

To view/test the frequency, as a result of Vtune we placed a test point.

To map the frequency output values Vs Vtune we conducted an experiment.

VCO Experiment

Motivation:

• The experiment has two main purposes.

• Check power and frequency in output/test point.

• To examine the frequency output values Vs Vtune.

VCO Experiment

Schema:

Out Test

Spectrum Analyzer

8V24V

50 Ohm

VCO-POS2000

POWER

VCO Experiment Conclusions and recommendations:

• VCO worked as expected.• There is difference in power output between the

datasheet to the actual value. (result of wire and connector losses)

• The difference between test pin to the output pin is -21dB.

• When needed to know the output frequency you can measure Vtest with a spectrum analyzer.

• If Vtest is not used, connection of a resistor of 50 ohm is preferred.

Mixer

Schema:

input RF MixerSRA-220

2,5,6,7

3

8

GND

1 .input LO

output IF

150R

37.5R

300R

50smaR

250R

Test

Finishing steps for the basic unit

Prepare the filters and gains for wire up. Build (schema in page 19) an energy

detector and an antenna. Connect all the devices and conduct an

experiment when the VCO is simulating the cellular device.

Sum the results and conclusions.

Full system

schema: Antenna

-1dB

26dB 26dB

Energy Detector

L.Pass400Mhz

H.Pass800Mhz

L.Pass900Mhz 20dB

L.O 1.15Ghz

Mixer

-1dB -1dB

-7dB

20dB

H.Pass1.7Ghz

L.Pass1.9Ghz 20dB

L.O 1.5Ghz

Mixer

-1dB -1dB

-7dB

20dB

sum

3

Future plans

Build the test case described in the Basic Unit.

Test the partial design.Create 1 directional antenna.Test the complete circuit including a

directional antenna and 3 basic units.Build the system <-> CPU interface.Test the system.