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Tuners
Stub Tuners

Stub tuners are basic laboratory tools used for matching load impedances to provide for maximum power transfer between a generator and a load, and introducing a mismatch into an otherwise matched system. Typical applications include power and attenuation measurements, tuned reflectometer systems and providing a DC return for single-ended mixers and detectors.

Stub tuners are impedance transformers that are designed to introduce a variable shunt susceptance into a coaxial transmission line. They consist of one or more short-circuited, variable length lines (stubs) connected at right angles to the primary transmission line. Each stub must be movable over one-half wavelength at the lowest frequency of operation in order to provide all possible shunt susceptances; therefore, the low frequency limit of a tuner is determined by the frequency at which the maximum stub travel equals one-half wavelength. Tuners, particularly multiple-stub models, are still usable below this limit. Other than the limitation of the connectors, there is no higher frequency limit; however, various models are offered for size convenience.

The spacing between the stubs of multiple-stub tuners determines the range of impedances that can be matched and the ease of tuning . The stub spacing of Maury double- and triple-stub tuners has been selected for general broadband applications. Triple-stub tuners are more convenient to use since tuning sensitivity is relatively independent of stub spacing.

Maury produces a comprehensive line of broadband stub tuners designed to satisfy the majority of applications. These tuners are available in double- and triple-stub configurations with frequency ranges extending from 0.2 to 18.0 GHz.


2612C2


1819A

 

Stub Tuner Reference Chart

Type
Frequency
Range
(GHz)
Connector - Model
Stub Travel
Stub Spacing
Type N 1
7mm 2
SMA 3
Inches

(cm)

Inches

(cm)

Double-Stub

0.2
-

0.5

1778G

2612B7

---

30.00

(76.2)

4.6

(11.7)

0.4
-

1.0

1778A

2612B1

1719A

15.00

(38.1)

4.6

(11.7)

0.8
-

4.0

1778B

2612B2

1719B

7.50

(19.1)

2.0

( 5.1)

2.0
-

12.0

1778C

2612B3

1719C

3.00

( 7.6)

0.75

( 1.9)

2.0
-

18.0

1778E

---

---

3.00

( 7.6)

0.5

( 1.3)

4.0
-

18.0

1778D

2612B4

1719D

1.75

( 4.4)

0.5

( 1.3)

Triple-Stub

0.2
-

0.5

1878G

2612C7

---

30.00

(76.2)

4.6

(11.7)
/

2.0

( 5.1)

0.4
-

1.0

1878A

2612C1

1819A

15.00

(38.1)

4.6

(11.7)
/

2.0

( 5.1)

0.8
-

4.0

1878B

2612C2

1819B

7.50

(19.1)

1.0

( 2.5)
/

0.75

( 1.9)

2.0
-

18.0

1878C

2612C3

1819C

3.00

( 7.6)

0.75

( 1.9)
/

0.5

( 1.3)

4.0
-

18.0

1878D

2612C4

1819D

1.75

( 4.4)

0.75

( 1.9)
/

0.5

( 1.3)

1 Precision stainless steel N per Maury data sheet 5E-049.

2 5E-060.

3 Precision stainless steel SMA per MIL-C-39012.

Copyright 2006 by Maury Microwave Corporation. All rights reserved.