Micro-Coax delay lines are a highly reliable method
of providing short delays in RF and Microwave systems.
We specialize in solving unique coaxial delay line packaging
and electrical problems. Our custom delay lines offer
an unbeatable combination of high performance, low cost
and quick delivery.
Our application engineers will work with you to custom
configure a delay line that satisfies your unique electrical
and packaging requirements. Outlined below are key delay
line design considerations:
Configuration:
Circular coils provide the most economical and consistent
delay line package since they facilitate repeatable
manufacture and test. Overall delay line performance
is further enhanced with circular configurations as
precise connector locations can be easily achieved.
Other configurations such as oval or square are possible
when packaging constraints require but these are expensive
to coil and usually require an invasive service loop
to compensate for cable physical length variations.
Length Tolerances:
Length should be specified electrically in lieu
of physically, since the physical length for a specified
electrical length may vary. We recommend tolerances
of ± 15 to ± 20 pico-seconds at frequencies between
800 and 2000 MHz. If necessary, the electrical tolerance
may also be specified in degrees. Furthermore, since
mechanical forming may induce electrical length changes,
we recommend that final electrical testing and trimming
be performed on fully coiled delay lines.
Cable Types:
Standard MIL-C-17 Semi-Rigid Cables use a solid
PTFE dielectric with inherently large phase (electrical
length) variations which may affect system performance
or require additional components in your system to compensate.
To minimize variations, Micro-Coax recommends low-loss
"LL" micro-porous PTFE dielectrics. These
dielectrics are very stable electrically eliminating
the need to compensate within the system for cable
length changes.
Packaging:
We recommend solder tacking as the most effective
method to ground and maintain configuration in lieu
of tie wrapping or tape. Where connectors are a concern,
the delay lines may be configured with SMT ready leads
or premounted on PCB substrates for pick-and-place.
System Design:
We recommend that the delay lines be considered
throughout the system design process. Delay lines with
long and complicated rigid leads are expensive, difficult
to ship and ungainly to assemble. Also, any long leads
are easily damaged, potentially affecting system performance.
Micro-Coax can help to minimize design difficulties
by:
- Nesting multiple delay lines together for maximum
space utilization.
- Integrating high performance flexible cables directly
into the delay line package thus eliminating the need
for additional interconnects.
Key Features:
- Tolerances to less than 15 picoseconds
- Low density PTFE dielectrics to maximize phase stability
over temperature extremes from -65° C to 250° C
- Automated production lines to minimize cost and
maximize performance
- Multiple coils and delays in one package
- Single or double layers of cable to minimize height
- Integrated flexible leads
Applications:
- Amplifiers for cellular base stations
- Land mobile radio transmitters and receivers
- Radar systems
- ECM systems
- Microwave altimeters
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