Delay Lines


INTRODUCTION

Microwave delay devices are designed and manufactured to meet delay requirements in frequency ranges from UHF through KA-Band. Several techniques are used to achieve the delays. It is the responsibility of the design engineer to decide about the best method for delaying the signals in his particular application. The decision depends on the frequency range, the delay needed, the VSWR, the suppression of undesired signals, the size of the device and its form, and last but not least the price of the device will be an important factor.

Coaxial Delay Line

The coaxial delay line is the classical device. The length of the delay line can easily be calculated from the propagation delay of the signal within the coaxial cable and the delay needed. Other advantages are the good electrical performance of the professional delay line, the usually fast availability and the attractive price. Disadvantages are in some cases the large size and the high insertion loss, especially for longer delays at higher frequencies.

Spectrum Elektrotechnik GmbH offers a wide variety of coaxial delay lines. All the designs use Semi-Rigid Cable, from very small diameters, such as 0.047" up to diameters of 0.250", for certain applications even bigger. The Semi-Rigid Cables are using either Solid Dielectric, or Low Density Dielectric. The advantage of the Low Density Dielectric is lower insertion loss, a wider temperature range and better performance over temperature.

All Delay Lines are made to the customer specifications: a specific delay that is needed in the applications, a minimum attenuation, a maximum return loss, a minimum change over temperature, a certain mechanical configuration and for an environment that often only allows the best.

 

DELAY LINES PACKAGING OPTIONS

The delay line can be packaged in a number of different ways, such as:

  • An especially designed housing:
    It can be made of any kind of material, although mostly used is excavated aluminum.
  • 19" Rack Mounting:
    This is common for larger delay lines, or for applications in laboratories or test sets.
  • Spool Mounting:
    This is an economical way of packaging, using a spool as supporting and mounting fixture.
  • Free Coils:
    This is definitely the most inexpensive packaging, winding the delay line in a free coil and then using either tape, plastic or stainless steel ties, or just solder, to hold the delay line together.

 

QUICK REFERENCE

The following Table can be used as a quick reference. Comparing the data of the different cables listed in attenuation, diameter, length and weight will allow a fast decision about which cables may be suited best in a specific application.

Dielectric Cable P/N Code Outer Dia. Attenuation dB
(10 GHz)
Phase Stability Min. Bend Radius
(mm)
Length nom.
(m)
Weight
(g)
10 ns50 ns100 ns10 ns50 ns100 ns10 ns50 ns100 ns
Low-density 421-307 05 0.085" 5.00 24.9 49.8   15.2 2.33 11.6 23.3 54 272 544
422-700-3 --- 0.085" 4.2 21.1 43.3   15.0 2.43 12.2 24.3 50 250 501
421-069 --- 0.116" 3.10 15.5 31.0 Best 17.8 2.53 11.7 23.5 82 408 816
421-298 98 0.141" 2.40 12.0 24.0 Best 25.4 2.43 12.2 24.3 100 499 998
422-900-3 141L 0.141" 2.24 11.2 22.4   25.4 2.43 12.2 24.3 102 508 1017
421-336 36 0.250" 1.12 5.6 11.2 Best 50.8 2.40 12.0 24.0 327 1633 3266
421-281 81 0.250" 1.12 5.6 11.2 Best 50.8 2.40 12.0 24.0 181 907 1814
Solid RG-405 (421-086) 89 0.086" 5.22 26.10 52.2 Note "A"* 5.1 2.12 10.6 21.2 45 226 454
RG-402 (421-669) 69 0.141" 2.92 14.60 29.2 Note "A"* 8.9 2.12 10.6 21.2 100 499 998
RG-401 (421-252) 52 0.250" 1.80 9.0 18.0 Note "A"* 12.7 2.12 10.6 21.2 318 1588 3175
421-250 50 0.250" 1.80 9.0 18.0   12.7 2.12 10.6 21.2 315 1575 3150
* "A" - At higher temperatures, 21°C to 120°C, microporous PTFE dielectric Cable has only slightly better phase response than solid PTFE dielectric cable. However, from 21°C to -50°C microporous cable displays far superior phase response.

 

QUICK RESPONSE MANUFACTURING

The Quick Response Manufacturing is another good example for the commitment to providing excellent Customer Service. The Quick Response Group was implemented to react immediately to customers' needs. Sometimes Products will be shipped within 24 hours. All Products manufactured in the Quick Response Area will meet the same Quality Standard as all the other products, they are submitted to the same inspection criteria, they are tested with the same procedures as used on standard products.

Contact Details
Spectrum Elektrotechnik GmbH
Olschewskibogen 1
80935 Munich
Germany

Mailing address:
P.O. Box 450 533
80905 Munich

+49 (0)89 / 354 804-0
+49 (0)89 / 354 804-90

sales@spectrum-et.com
www.spectrum-et.com