HP 8491A/B, 8492A, 8493A/B/C,
11581A, 11582A and 1 1583A/C
Coaxial Attenuators
Product Overview
dc to 26.5 GHz
• High accuracy
• Low SWR
• Broadband frequency coverage
• Small size
Description
Hewlett-Packard coaxial fixed
attenuators provide precision
attenuation, flat frequency response,
and low SWR over broad frequency
ranges (dc to 26.5 GHz) at low prices.
Attenuators are available in eight
attenuation values: 3, 6, 10, 20, 30,
40, 50, and 60 dB; with performances
specified from dc to 26.5 GHz; and
with choice of four connector types:
Type-N, APC-7, SMA
1
, and APC 3.52.
These attenuators are all tested on
a state-of-the-art HP precision analyzer to assure specifications over
the full frequency ranges. Although
the HP 8493C is not specified above
26.5 GHz, it performs resonance
free to 34 GHz with only a small
loss in performance.
These connectors are stainless steel
for long wear and high repeatability.
The HP 8492A is furnished with
Amphenol precision 7 mm
connectors (APC-7). These sexless
connectors have a clearly defined
reference plane for precise and
unambiguous measurements.
The HP 8493A/B attenuators are
furnished with SMA type connectors.
The connectors are heat treated
beryllium copper for greater
strength and wear.
The HP 8493C is furnished with
the APC 3.5 connector which is
compatible with standard SMA
connectors but is more rugged and
offers improved repeatability over
hundreds of connections.
Precision construction
The attenuators employ a film on
an attenuator card as the resistive
element. The uniformity and repeatability of the film deposition process
result in high accuracy and low SWR
over very wide frequency ranges.
The HP 8493C features thin-filmtantalum nitride on a sapphire
substrate for exceptional precision
performance to 26.5 GHz. In fact, it
performs resonance-free to 34 GHz,
the top frequency limit of the
APC-3.5 connector.
The choice of connector type and
material also ensure accurate and
repeatable attenuation. The
HP 8491A/B attenuators are
furnished with Type-N connectors
whose dimensions are compatible
with either MIL-C-71 or MIL-C39012 connector specifications.
1. As per USASI Committee C83.2 compatible
with OSM, ARM, WPM, BRM, NPM, etc.
2. Mate with MIL-C-71 or MIL-C-39012
connectors.
HP 8493C
HP 8493A/B
HP 8492AHP 8491A/B
2
Description (cont’d)
Quality assurance in testing
The flat frequency response and low
SWR of the attenuators are assured
over the entire frequency range by
full frequency band testing on a
state-of-the-art HP precision
analyzer. Full frequency band
testing ensures that narrow resonances in the frequency band are
not overlooked. Actual attenuation
values taken at dc, 4, 8, 12, 18, and
26.5 GHz are stamped on the
attenuator body for permanent and
easy reference.
Testing each attenuator with a
state-of-the-art HP precision analyzer brings standards lab accuracy
to production testing because the
system can determine its own
measurement uncertainties and
compensate for them in the testing
process. System calibration is derived
from precise physical standards
which are directly traceable to the
National Bureau of Standards. In
addition, automatic testing eliminates
the possibility of human error in
setting instrument controls, taking
data, or making calculations.
Applications
Ruggedness, reliability and small
size make these attenuators useful
both on the bench and in systems
applications. With their high accuracy
and low SWR they are ideally suited
for extending the range of sensitive
power meters for higher power
measurements and for “padding”
poorly matched devices to improve
system SWR.
These same characteristics lend
themselves to applications as calibration standards in attenuation
and RF substitution measurements.
With their broad dc to 26.5 GHz
frequency range and reasonable
cost, general applications, such as
the reduction of power level to
sensitive components and instrumentation systems, are attractive
and appropriate uses for these
attenuators.
Accuracy
The accuracy of an attenuator
directly affects the accuracy of the
measurement where the attenuator
is used. In fact, attenuators are
used extensively as the standard
against which other instruments or
devices are calibrated.
HP’s fixed attenuators achieve flat
frequency response (typically a few
hundredths of a dB) and overall
accuracy (typically ±2 % of value
in dB at 26.5 GHz) through the use
of thin-film attenuator cards. These
cards are composed of high stability
tantalum nitride resistive film
deposited on a sapphire or alumina
substrate.
Quality assurance
in specifications
The following examples demonstrate
the reliability and comprehensiveness
of specifications. Although the absolute accuracy for a 3-dB attenuator
is specified as ±0.3 dB, test data
statistics indicate an expected
value of 3 dB ±0.20 dB from dc to
18 GHz. Similarly a 30-dB attenuator is specified as ±1.0 dB, but
typically is no worse than 30 dB
±0.75 dB from dc to 18 GHz. The
other attenuation values are also
specified as conservatively.
In addition, Hewlett-Packard
precision attenuators meet more
comprehensive performance standards. Linear phase response is an
example. Not only is wide bandwidth
significant, but also linear phase
response is an important parameter
for applications where pulse distortion
must be kept to a minimum. The
excellent linearity of the HP attenuators is typified in the accompanying illustration of an actual network
analyzer measurement.
Economy
Automated procedures have resulted
in economies of scale in production
and testing. The automated resistive
film deposition process permits
high-volume manufacture with
excellent yield. Furthermore,
characteristics are consistently
uniform; hand “touch-up” is not
required to meet specifications.
Automatic testing means exceptionally thorough, high-accuracy measurements can be performed in
appreciably shorter time than could
be done manually.
The overall result is outstanding
attenuator performance at
attractive prices.
Center trace is phase response of HP 8491A
–6 dB attenuator from 1.0 to 2.0 GHz taken
with HP 8410 network analyzer. Top and
bottom traces are ±1° calibration. Linear
phase component has been compensated for
with a line stretcher. Response, therefore,
shows nonlinear phase deviation of < ± 1/2°
over 1 to 2 GHz band.
Table 2.
Coaxial attenuator calibration frequencies* (MHz)
100 4500 9000 13000 16750
500 5000 9500 13500 17000
1000 5500 10000 14000 17250
1500 6000 10500 14500 17500
2000 6500 11000 15000 17750
2500 7000 11500 15500 18000
3000 7500 12000 16000 (each 250 MHz
3500 8000 12400 16250 to 26.5 GHz)
4000 8500 12500 16500
*dc to 12.4 GHz models include 26 frequencies, dc to 18 GHz models
include 42 frequencies, dc to 26.5 GHz models include 67 frequencies
(2 to 26.5 GHz).
3
Calibration Data
Optional calibration data
Use of calibration data has always
been an effective means of reducing
measurement uncertainty at RF
and microwave frequencies. This
data is available for HP’s fixed
attenuators as Option UK6. Data
which is generated by an automatic
network analyzer provides a
tabulated list of attenuation and
SWR’s at 26 to 67 frequencies (see
Table 2). Measurements to 60 dB
are directly traceable to NBS
standards and feature very low
measurement uncertainties. Option
UK6 data is available when the
attenuators are first purchased and
recalibrations are available through
HP Customer Service Centers
around the world.
Table 1. SWR data uncertainties
SWR Data Uncertainties
Connector Frequency Measured SWR Measured SWR
Type Range (GHz) 1.0 to 1.35 1.35 to 1.86
APC 7 & Male dc to 12.4 ±0.025 ±0.041
Type-N 12.4 to 18.0 ±0.031 ±0.050
Female dc to 8.0 ±0.025 ±0.046
Type-N 8.0 to 12.4 ±0.031 ±0.063
12.4 to 18.0 ±0.042 ±0.071
Male SMA dc to 8.0 ±0.031 ±0.054
8.0 to 12.4 ±0.045 ±0.084
12.4 to 18.0 ±0.077 ±0.137
Female SMA dc to 8.0 ±0.054 ±0.088
8.0 to 12.4 ±0.077 ±0.132
12.4 to 18.0 ±0.122 ±0.206
Male APC-3.5 dc to 10 ±0.025 ±0.041
10 to 18 ±0.031 ±0.050
18 to 26.5 ±0.045 ±0.067
Female dc to 10 ±0.020 ±0.030
APC-3.5 10 to 18 ±0.025 ±0.037
18 to 26.5 ±0.035 ±0.050
Table 3. Attenuation data uncertainties
Attenuation HP 8491, 8492 and 8493 Attenuation data uncertainty
(dB) (dB)
0.1 to 2.0 2 to 6 6 to 12.4 12.4 to 18.0 18.0 to 26.5
GHz GHz GHZ GHz GHz
3 ±0.07 ±0.06 ±0.06 ±0.11 ±.15
6 ±0.07 ±0.07 ±0.07 ±0.11 ±.15
10 ±0.08 ±0.07 ±0.07 ±0.12 ±.15
20 ±0.09 ±0.08 ±0.08 ±0.13 ±.15
30 ±0.12 ±0.11 ±0.11 ±0.15 ±.l 8
40 ±0.15 ±0.14 ±0.14 ±0.21 ±.25
50 ±0.23 ±0.23 ±0.23 ±0.34 n/a
60 ±0.50* ±0.48* ±0.90* ±0.90* n/a
*The uncertainties noted represent 99.7 % probability values.
Ordering Information
To order, basic model number and option (specifies
attenuation value) must be specified. Option UK6
calibration data can also be ordered with the basic
model number and attenuation value option.
Ordering example:
HP 8491A Option 003, Option UK6
003
006
010
020
030
040
050
060
30 dB
40 dB
50 dB
60 dB
Optional calibration
data
3 dB
6 dB
10 dB
20 dB
4
Specifications
Specifications describe the instruments warranted performance. Supplemental characteristics (shown in italics) are intended to provide
information useful in applying the instrument by giving typical, but non-warranted, performance parameters.
Attenuation accuracy:
Environmental
Temperature, non-operating: –55 ° to +85 °C.
Temperature, operating: 0 ° to +55 °C.
EMC: Radiated interference is within the requirements
of MIL STD 461 method RE02, VDE 0871 EN55011 and
FCC part 18.
HP 8491A/93A HP 8491B/93B/92A HP 8493C
dc to 12.4 GHz dc to 12.4 12.4 to 18 GHz dc to18 18 to 26.5 GHz
3 dB ±0.3 dB ±0.3 dB ±0.5 dB ±I.0 dB
6 dB ±0.3 dB ±0.3 dB ±0.4 dB ±0.6 dB
l0 dB ±0.5 dB ±0.6 dB ±0.3 dB ±0.5 dB
20 dB ±0.5 dB ±0.6 dB ±1.0 dB ±0.5 dB ±0.6 dB
30 dB ±1.0 dB ±1.0 dB ±0.7 dB ±1.0 dB
HP 8491A only HP 8491B/92A only
40 dB ±1.5 dB ±1.5 dB ±1.0 dB ±1.3 dB
50 dB ±1.5 dB ±1.5 dB N/A
60 dB ±2.0 dB ±2.0 dB N/A
HP 8491B/8493B HP 8492A HP 8493C
HP 8491A/8493A
dc to 8 8 to 12.4 12.4 to 18
(GHz) (GHz) (GHz) dc to 8 8 to 12.4 12.4 to 18 dc to 8 8 to 12.4 12.4 to 26.5
3 dB 1.25 1.35 1.5 1.2 1.3 1.5 1.10 1.15 1.25
6 dB 1.2 1.3 1.5 1.2 1.3 1.35 1.10 1.15 1.27
10 dB 1.2 1.3 1.5 1.15 1.25 1.3 1.10 1.15 1.25
20 dB 1.2 1.3 1.5 1.15 1.25 1.3 1.10 1.15 1.25
30 dB 1.2 1.3 1.5 1.15 1.25 1.3 1.10 1.15 1.25
HP 8491A/B only HP 8491B only
40 dB 1.2 1.3 1.5 1.15 1.25 1.35 1.10 1.15 1.25
50 dB 1.2 1.3 1.5 1.15 1.25 1.35 N/A N/A N/A
60 dB 1.2 1.3 1.5 1.15 1.25 1.35 N/A N/A N/A
SWR:
HP 8491A HP 8493A HP 8491B HP 8493B HP 8492A HP 8493C
Connectors (50 Ω) Type-N
2
SMA
1
Type-N
2
SMA
1
APC-7 APC-3.5
3,6,10,20 dB 30,40 dB
Dimensions Millimeters 67 X 21 40 X 13 67 X 21 40 X 13 70 X 21 33.8 X 8 36.8 X 8
Inches 2 7/16 X 13/16 D l 9/16 X 1/2 D 2 7/16 X 13/16 D l 9/16 X 1/2 D 2 3/4 X 13/16 D l 5/l6 X 5/l6 D 1 7/16 X 5/16 D
Net 110 g (4 oz) 30 g (1 oz) 110 g (4 oz) 30 g (1 oz) 110 g (4 oz) 8.5 g 9.4 g
Weight (0.3 oz) (0.33 oz)
Shipping 220 g (8 oz) 220 g (8 oz) 220 g (8 oz) 220 g (8 oz) 220 g (8 oz) 45 kg (1 Ib.)
Frequency range:
HP 8491A and 8493A, dc to 12.4 GHz
HP 8491B, 8493B and 8492A, dc to 18 GHz
HP 8493C, dc to 26.5 GHz
1. As per USASI Committee C83.2 compatible with OSM, ARM, WPM, BRM, NPM, etc.
2. Mate with MIL-C-71 or MIL-C-39012 connectors.
3 At 20 °C derated to l.3 W avg. at 55 °C.
Supplemental characteristics
Temperature Stability:
0.000l dB/dB/°C (all except HP 8493C)
0.0002 dB/dB/°C (HP 8493C)
Maximum input power: 2 W avg., 100 W peak
3
Power sensitivity: 0.001 dB/dB/W (all except HP 89430)
0.001 dB/W (HP 8493C)
Attenuator sets
HP 11581A/11582A/11583A/11583C
A calibrated set of four HP fixed coaxial attenuators (3, 6, 10, and 20 dB)
is available. Each set includes a calibration report certified traceable to the
National Bureau of Standards. The reports included with the HP 11581A,
11582A, 11583A and 11583C indicate the accuracy of measurement and list
the attenuation and reflection coefficient at each port of the attenuator.
The set of four attenuators is furnished in a handsome walnut accessory
case. In addition to protecting the units when not in use, the case is also a
convenient storage place for the attenuators and the calibration reports.
Calibration data as described on page 3 is included with rack attenuator set.
Ordering Information
HP 11581A (3,6,10,20 dB values HP 8491A)
HP 11582A (3, 6,10,20 dB values HP 8491B)
HP 11583A (3, 6, 10, 20 dB values HP 8492A)
HP 11583C (3, 6, 10, 20 dB values HP 8493C)
For more information about
Hewlett-Packard test and measurement products, applications,
services, and for a current sales
office listing, visit our web site,
http://www.hp.com/go/tmdir. You
can also contact one of the following
centers and ask for a test and
measurement sales representative.
United States:
Hewlett-Packard Company
Test and Measurement Call Center
P.O. Box 4026
Englewood, CO 80155-4026
1 800 452 4844
Canada:
Hewlett-Packard Canada Ltd.
5150 Spectrum Way
Mississauga, Ontario
L4W 5G1
(905) 206 4725
Europe:
Hewlett-Packard
European Marketing Centre
P.O. Box 999
1180 AZ Amstelveen
The Netherlands
(31 20) 547 9900
Japan:
Hewlett-Packard Japan Ltd.
Measurement Assistance Center
9-1, Takakura-Cho, Hachioji-Shi,
Tokyo 192, Japan
Tel: (81) 426 56 7832
Fax: (81) 426 56 7840
Latin America:
Hewlett-Packard
Latin American Region Headquarters
5200 Blue Lagoon Drive, 9th Floor
Miami, Florida 33126, U.S.A.
Tel: (305) 267-4245
(305) 267-4220
Fax: (305) 267-4288
Australia/New Zealand:
Hewlett-Packard Australia Ltd.
31-41 Joseph Street
Blackburn, Victoria 3130, Australia
1 800 629 485
Asia Pacific:
Hewlett-Packard Asia Pacific Ltd.
17-21/F Shell Tower, Times Square,
1 Matheson Street, Causeway Bay,
Hong Kong
Tel: (852) 2599 7777
Fax: (852) 2506 9285
Data Subject to Change
Copyright © 1997
Hewlett-Packard Company
Printed in U.S.A. 8/97
5953-6475
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