COM-power corporation AH-840 User manual

HORNANTENNA
18 - 40 GHz
MODEL AH-840
rev: 030402

WARRANTY
All equipment manufactured by Com-Power Corporation is warranted against defects in
material and workmanship for a period of two (2) years from the date of shipment. Com-Power
Corporation will repair or replace any defective item or material if notified within the warranty
period.
You will not be charged for warranty service performed at our factory. You must, however,
prepay inbound shipping costs and have a return authorization.
This warranty does not apply to:
a) products damaged during shipment from your plant or ours.
b) improperly installed products.
c) products operated outside their specifications.
d) improperly maintained products.
e) products which have been modified.
f) normal wear of material.
g) calibration.
Any warranties or guarantees, whether expressed or implied, that are not specified set forth
herein, will not be considered applicable to any equipment sold or otherwise furnished by Com-
Power Corporation. Under no circumstances does Com-Power Corporation recognize or assume
any liability for any loss, damage or expense arising either directly or indirectly from the use or
handling of products manufactured by Com-Power Corporation, or any inability to use them
separately or in combination with other equipment or material.
The warranty is void if items are shipped outside the United States, without prior approval of
Com-Power Corporation.
Warranty Limitations
The above warranty shall not apply to defects resulting from improper or inadequate maintenance
by the buyer, unauthorized modification or misuse, operation exceeding specifications, or im-
proper site preparation.

AH-840 Horn Antenna
The model AH-840 HornAntenna is designed to be used in an EMI laboratory to
measure and/or to generate electro-magnetic E (electric) fields.
Generating Electro Magnetic Fields:
The model AH-840 antenna should be operated by trained personnel in the
field of EMC for the purpose of generating electro-magnetic fields. Test location
should be carefully selected to avoid interference to other equipment and
exposure of personnel to high electromagnetic fields.
Maintenance and Service:
There are no user serviceable parts in the antenna. However, the user should peri-
odically check the antenna for any deformed elements or dents on the antenna
caused by accident during use. Com-Power recommends calibration of the an-
tenna be checked once a year (If used in accordance toANSI C63.4-1992 Section
4.4 Calibration of Measuring Equipment). Com-Power provides calibration ser-
vice for all equipment sold. Call the factory if calibration or other service is de-
sired.
SAFETY PRECAUTIONS

AH-840 Horn Antenna
About this Manual
This manual provides instructions for testing and using the Model
AH-840 Horn Antenna.
Information contained in this manual is the property of Com-Power
Corporation. It is issued with the understanding that none of this
material may be reproduced or copied without written permission
from Com-Power.
If you encounter problems while using the Model AH-840 Horn
Antenna, contact Com-Power Corporation at [phone].
If You Need
Assistance
iv

AH-840 Horn Antenna
Contents
v
List of Figures
Section Page
1 General Information.................................................................... 1-1
1.1 Introduction ........................................................................................... 1-1
1.2 General Description............................................................................. 1-1
1.3 Equipment Specifications ................................................................... 1-2
1.4 Equipment, Accessories, and Documents Supplied ...................... 1-2
2 Connecting Procedures............................................................. 2-1
2.0 Introduction ........................................................................................... 2-1
2.1 Antenna Setup...................................................................................... 2-1
3 Theory of Operation ................................................................... 3-1
3.0 Overview................................................................................................ 3-1
3.1 Theory of Operation ............................................................................ 3-1
1-1 AH-840 (picture)................................................................................... 1-2
1-2 Typical Antenna Factors...................................................................... 1-3
1-1 Equipment Specifications ................................................................... 1-2
1-2 Power Requirement & Gain (typ.) .................................................... 1-3
List of Tables

AH-840 Horn Antenna
General Information 1
This section includes the following:
a) Introduction
b) General Description
c) Specifications
d) Equipment Supplied
1-1
1.1 Introduction
This section contains general description of the Horn antenna
model AH-840. This section also contains general performance
and background information about the antenna.
1.2 General Description
The Model AH-840 Horn antenna was specifically designed for
EMI measurement from 18 to 40 GHz. The antenna is capable
of receiving and transmitting signals.
The Horn antenna is a transducer which converts electric field
strength in dBV/m to Volts that can be displayed on a spectrum
analyzer or EMI meter.
Setting up using the antenna is described in section 2. Informa-
tion on theory of operation is given in section 3.
1.3 Equipment Specifications
The specification for AH-840 Horn antenna are listed in Table 1-1.
1.4 Equipment, Accessories, and Documents Supplied
Equipment, accessories, and documents supplied with the Antenna are
as follows:
a) HornAntenna
b) User's Guide
c) Calibration information

AH-840 Horn Antenna
1-2
Model: AH-840 Horn Antenna
ELECTRICAL
Frequency Range: 18 - 40 GHz
VSWR (Typ.) 2.0 : 1.0
Gain, dBi (Typ.) See Table 1-2
Antenna Factor (Typ.) See Figure 1-2
Power Handling: 5 Watts CW
Impedance: 50 Ω, nominal
Polarization: Linear
Connector Type: K- Female
MECHANICAL
Dimensions 7.35" long (18.67 cm)
2.65" wide (6.73 cm)
1.98" high (5.03 cm)
Weight: 2 lbs. (.909 kg), max.
Table 1-1 Equipment Specifications
Figure 1-1 AH-840 Horn Antenna

AH-840 Horn Antenna
Table 1-2 Power Requirements and Antenna Gain
(typical)
Figure 1-2 TypicalAntenna Factors
1-3
0.0
10.0
20.0
30.0
40.0
50.0
Frequency (GHz)
Power Requirement (Watts) at 1 meter spacing to obtain field strength:
Frequency Field strength Gain
GHz E E E (dBi)
10 V/m 50 V/m 100 V/m
18 0.05 1.15 4.61 18.6
20 0.03 0.80 3.18 20.2
22 0.03 0.76 3.04 20.4
24 0.02 0.62 2.47 21.3
26 0.02 0.50 2.01 22.2
28 0.01 0.32 1.27 24.2
30 0.01 0.32 1.30 24.1
32 0.02 0.51 2.05 22.1
34 0.02 0.38 1.52 23.4
36 0.02 0.51 2.06 22.1
38 0.03 0.82 3.26 20,1
40 0.04 1.00 4.01 19.1

AH-840 Horn Antenna
This section explains the following:
a) Introduction
b) Setup
Setup Procedure 22-1
2.0 Introduction
This section describes antenna setup and mounting for EMI measurement.
2.1 Antenna Setup
2.1.1 Connecting
The model AH-840 horn antenna has a Type K- Female connector. This connector
is used for antenna output and input.
2.1.2 Antenna setup for receiving signals
The modelAH-840 must be connected to the spectrum analyzer with microwave
frequency rated, low loss coaxial cabling. The losses must be measured and
accounted for when in calculating / measuring the field strength.
2.1.3 Antenna setup for transmitting signals
When the AH-840 antenna is used for transmitting signals, the antenna is con-
nected to a microwave signal generator and power amplifier. The modelAH-840
antenna can transmit up to 5 Watts of continuous power. The field generated by
the antenna can be measured by using a field strength meter or another horn
antenna withen their respective limits.

AH-840 Horn Antenna
2.1.4 Test location
The Horn Antenna must be mounted and placed in area away from other conduc-
tive objects or materials when in use. Large conductive building, structures and
electrical cables, can reflect and reradiate the emissions of EUT, causing errors in
the test data. In addition, care should be taken to keep measuring instruments and
test personnel away from the test area to avoid interference to the test, as well
exposure of test personnel to high electromagnetic fields.
2-2

AH-840 Horn Antenna
Theory of Operation 3
This chapter explains the following:
a) Overview
b) Theory of Operation
3-1
3.0 OverviewThis section describes the theory of operation of the Horn Antenna.
3.1 Theory of Operation
Broadband antennas allow measurement of signals over a wide frequency
range. These antennas do not require any tuning or balun switching during
measurement. Models AH-840 HornAntennas are broadband antennas that
operate in the frequency range of 18 GHz - 40 GHz.
The modelAH-840 can both Receive and Transmit over the frequency
range of operation and is used for susceptibility and emissions testing in
EMC Laboratories.
Before the Horn antennas are used for measurement they have to be
calibrated. Typically antenna calibration is performed in an open field test
site( OATS). During calibration a known field strength (dBV/m) is
generated around the antenna at each frequency at predetermined intervals
between 18 GHz - 40 GHz. The difference between field strength (dBV/m)
received by the antenna and known field strength generated ( dBV/m) is
the antenna factor (dB/m) for that frequency. During EMC testing the
antenna factor for the frequency of interest is added back to reading on
the EMI meter or spectrum analyzer to calculate the field strength
measured by the antenna.
Field strength (dBv/m) = Output measured (dBV) + Antenna Factor (dB/m)
When using the AH-840 antenna for transmitting application, please refer
to Table 1-2 to determine the power requirements to generate the desired
electro magnetic field.