Radar coaxial cable assemblies manufacturing process design process design (1)

Due to the variety of flexible, semi-flexible and semi-rigid radar RF coaxial cable assemblies produced and processed, the models are not the same, and the overall process requirements are basically the same. In the process sub-step, each control point of the process plays an important role in ensuring the quality and performance of the entire assembly. The negligence of any one link will lead to the performance of the entire component not meeting the requirements, which will lead to the failure of the entire system. The requirement of automatic tangent precision is relatively high, which is an important part of controlling the length of coaxial cable assemblies, which can effectively ensure the phase consistency between components. The automated stripping step is critical to maintaining pin and inner conductor coaxiality and matching coaxial cable assemblies to connectors. Automatic chamfering is a key point to ensure a tight fit between the cable and the pin. An important point in the welding process of coaxial cable assemblies is to prevent virtual welding, and at the same time, the control of temperature and time is very high, so as not to have a greater impact on standing waves and insertion loss.

1. Analysis of the manufacturing process
1.1 Tangent to coaxial cable assemblies. Generally, the inner conductor of coaxial cable assemblies is silver-plated copper wire or silver-plated clad steel wire, the outer conductor is usually made of tinned copper wire hot-dip tin process, and the insulating medium is PTFE. Since the connectors and insulating medium of coaxial cable assemblies are good conductors and good insulators, respectively, the line loss can be ignored, and the transmission speed calculation formula is

Further available wavelength calculation formula

In the formula, f is the working frequency; C is the propagation speed of microwave in vacuum, which is equivalent to the speed of light; ur is the relative permeability; er is the relative permittivity. Phase formula on transmission line:

L is the adjustment length. From this it can be seen that
Length variation is the main factor affecting the phase consistency index of coaxial cable assemblies between the same batch.
The method used for matching coaxial cable assemblies is mainly to ensure their electrical length through mechanical length. The electrical length is the decisive factor for the phase of the components. For multiple cable assemblies in the same batch to have relatively consistent phases, they must have consistent electrical lengths.

Specifically, it can be divided into two cases:
(1) For short coaxial cable assemblies (length ≤ 1m), the influence of the inhomogeneity of the medium inside the cable on the electrical length is not obvious and can usually be ignored. The method used for matching such components is to directly ensure their electrical length by ensuring the mechanical length. This requires the selected blanking equipment to meet the precision requirements, and the quality of the incision is good, and the mechanical length of the cables is highly consistent, so as to lay a good foundation for the consistency of the electrical length between the coaxial cable assemblies. Actual adjustments are also made depending on the frequency used and the required phase width.

(2) For long coaxial cable assemblies (length ≥ 1m), due to the non-uniformity of the medium, it is greatly affected. If only the same mechanical length is guaranteed, it will be found that the phase dispersion will be very serious after assembly. , At the same time, the amount of repair work and scrap will be very large. In the assembly process, a vector network analyzer should be used to measure the electrical length as an auxiliary means, and the electrical length should be consistent after cutting, and then assemble.

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