Willtek 4921 Data Sheet

Data Sheet

4921

RF Shield

Boosting wireless effi ciency

What’s the fastest way to get a comprehensive picture?

The 4921 RF Shield meets the needs of production and repair

centres in terms of isolation of the unit under test from

adjacent units and other RF equipment such as radio base

stations. It surpasses the stringent shielding requirements for

3G mobile phone testing of 80 dB attenuation between the

phone under test and other phones and base stations.

The RF absorption inside the 4921 RF Shield leads to low

refl ection within the box and thus supports high-precision,

stable RF measurement results with instruments connected

to the RF Shield, such as the 4400 Mobile Phone Tester Series.

For service centres and manufacturing lines, the 4921 RF

Shield is the optimum solution not only in terms of shielding

and measurement precision but also in terms of longevity,

giving the 4921 RF Shield a unique price-performance ratio.

The 4921 RF Shield is easy to use thanks to the solid rocker

arm lever and gas springs that allow the operator to smooth-

ly open and close the box, without using much force. When

closed, the lid is fi rmly locked.

A removable plate on the rear can be used to hold customer-

specifi c connectors, e.g. for an interface for remote-control-

ling the unit under test.

Highlights

More than 80 dB shielding•

Highly reliable and robust design, •

guaranteed number of open-close cycles

Portable thanks to low size and weight•

Complementing the 4916 Antenna Coupler•

Suitable for mobile phones of all sizes•

High shielding for reliable testing

The unit under test should be isolated from its environment

to prevent radiation from different sources from affecting

each other. This would result in unreliable or even wrong

test results, incorrectly adjusted transmitters or failed tests

although the equipment performs within specifi cations.

The 4921 RF Shield solves three problems that occur without

proper shielding:

It eliminates problems with adjacent mobiles (radiation •

from one mobile phone affecting measurements on the

other).

It eliminates problems with local base stations (signals •

from a real base station affecting the measurement, sig-

nals from the phone affecting calls on a real base station).

It protects the environment from the RF emitted by the •

device under test (DUT).

Most third-generation (3G) mobile phone systems are based

on CDMA technology, which puts new demands on test

2

environments compared to TDMA systems. Measurements in

CDMA systems require 80 dB of shielding because the mobile

will attempt to lock onto the strongest base station. Without

the RF Shield, the mobile would hence ignore the test signal

and try to lock onto a local network. Also, a receiver test close

to the sensitivity level of the mobile receiver could severely

affect test results. Testing the receiver via the antenna

requires the phone to be isolated from a real base station by

80 dB; without shielding, the mobile could receive the signal

from a close-by network transmitter at –25 dBm while trying

to detect a test signal at –104 dBm.

Absorption supports stable measurement
results

In a pure metal box, the RF signal inside is refl ected many

times from the metal walls. Depending on the frequency be-

ing used and the exact position of the unit under test, the re-

fl ections may attenuate or amplify the signal at the antenna.

Designed for a long life

High-volume service centres and production lines require

solutions that work reliably over a long period of time.

Willtek guarantees a high number of open-close cycles after

which all parts are still working and the isolation of the 4921

RF Shield is still as specifi ed.

This has been verifi ed in endurance tests and in line with

military standard VG 95737, Electromagnetic Compatibility of

Equipment – Part 15 Test Methods for Coupling and Shield-

ing, see fi gures.

Reliable and stable measurement results can only be ob-

tained, if the signal is not refl ected but absorbed.

The absorbing material inside the 4921 RF Shield ensures

that the receive and transmit signals are properly transmit-

ted from and to the unit under test, allowing stable and cor-

rect radio measurements.

4921 RF Shield with transmitting antenna in EMC laboratory Mechanical life test of the 4921 RF Shield

3

Specifi cations

Specifi cations valid within a period of one year after delivery and a

maximum of 50,000 open-close cycles; initial isolation signifi cantly

exceeds the values specifi ed.

RF shielding

Measured according to German military standard

VG 95737, “Electromagnetic Compatibility of Equipment – Part 15

Test Methods for Coupling and Shielding”, using a shielded RF cable

with at least 100 dB isolation.

Values indicated below are typical values; isolation exceeds 80 dB in

all the specifi ed frequency bands.

700 to 1000 MHz typ. 90 dB

1700 to 2000 MHz typ. 90 dB

2000 to 2500 MHz typ. 85 dB

5000 to 6000 MHz typ. 80 dB

Mechanical specifi cations

Connector N-type

Open-close cycles > 50,000 times

Dimensions (L x W x H)

Inside: 340 x 240 (1901) x 160 mm

Outside: 410 x 265 x 220 mm

Weight 4.8 kg (10.5 lbs)

1

Between the gas springs

Ordering Information

4921 RF Shield (N) M 248 346

(including RF cable N – N)

Rear panel for customisation M 300 850

4921 RF Shield and 4916 Antenna M 248 348

Coupler package (standard shuttle)

4916 Antenna Coupler and M 248 721

4921 RF Shield package (with XY Shuttle)

Shielding Service Kit (gas springs, M 248 349

fi nger stocks, cleaning agent, RF gasket)

Shielded RF cable (N – N), 1.5 m M 382 804

(high-performance Sucofl ex 104 cable)

Customised rear panels with individual RF and data connectors (e.g.

DB-9, Bluetooth antenna connector) are available on request. Please

contact your local Wireless Telecom Group sales offi ce or representa-

tive.

Wireless Telecom Group
Sales Offi ces

Willtek Communications GmbH
Ismaning
Germany
Tel: [phone]
Fax: [phone]
[e-mail]
www.willtek.com

Parsippany, NJ
USA
Tel: [phone]
Fax: [phone]

Cheadle Hulme, Cheshire
United Kingdom
Tel: [phone]
Fax: [phone]

Roissy
France
Tel: [phone]
Fax: [phone]

Singapore
Tel: [phone]
Fax: [phone]

Shanghai
China
Tel: [phone]
Fax: [phone]

© Copyright 2009 Willtek Communica­tions GmbH.
All rights reserved.
4921/DS339/0208a/EN

Note: Specifi cations, terms and conditions
are subject to change without prior notice.