Panel profile and method for manufacturing thereof
The present disclosure describes a pultruded panel profile with a sandwich structure and a method of manufacturing such a panel profile. The sandwich structure has at least one a core layer and surface layers on both sides of the sandwich structure. The core layer comprises at least one signal window section made of a signal-transparent material, the signal-transparent material being substantially transparent to at least one wireless signal. The core layer further comprises a peripheral section surrounding the signal window section, the peripheral section having a different material composition than the signal window section.
1 . A cover panel of a radome with a signal window, wherein
the cover panel has a pultruded sandwich structure with at least one a core layer and surface layers on both sides of the sandwich structure, the sandwich structure having a length extending along the pultrusion direction of the sandwich structure and a width perpendicular to the length,
the core layer comprises at least one signal window section made of an RF-transparent material,
the core layer further comprises a peripheral section comprising at least one reinforcing material and surrounding the signal window section, the peripheral section having a different material composition than the signal window section and comprising:
lengthwise peripheral portions extending along the length of the sandwich structure on both widthwise sides of the signal window section; and
widthwise peripheral portions extending along the width of the sandwich structure on both lengthwise ends of the signal window section, the widthwise peripheral portions comprising reinforcing structures made of discrete reinforcing elements which comprise the at least one reinforcing material and which have a main extension in a widthwise direction.
2 . The cover panel according to claim 1 , wherein the lengthwise peripheral portions comprise reinforcing structures made of continuous fibres having a main extension in a lengthwise direction.
3 . The cover panel according to claim 2 , wherein the thickness of the signal window section is configured to correspond with a length of one or multiple quarters of an effective wavelength of an RF signal traveling through the signal window section, the RF signal being in a nominal signal frequency range of an antenna in the radome.
4 . The cover panel according to claim 1 , wherein the signal window section is made of one or more natural or synthetic cellular materials.
5 . The cover panel according to claim 4 , wherein the fibres of the surface layers are in the form of woven fabric or layers thereof.
6 . The cover panel according to claim 5 , wherein the thickness of the foam is 0.1-50 mm and the thickness of the surface layers is 0.1-5 mm.
7 . A telecommunication antenna arrangement comprising an antenna and a radome protecting the antenna, wherein
the radome comprises a cover panel according to claim 1 ,
the thickness of the signal window section of the cover panel corresponds with a length of one or multiple quarters of wavelength an RF signal traveling through the signal window section, the RF signal having a frequency in a nominal signal frequency range of the antenna.
8 . A pultrusion method for manufacturing a cover panel of a telecommunication antenna radome with a signal window, the method comprising
providing a plurality of discrete core elements between two surface layers,
pulling the surface layers and the core elements therebetween through a pultrusion process, thereby forming a continuous cover panel profile with a sandwich structure, the panel profile having a length extending along the pultrusion direction of the panel profile and a width perpendicular to the length,
cutting the continuous cover panel profile at predetermined lengths to form the cover panel,
wherein
the discrete core elements comprise at least two different types of elements, the two different types including an RF-transparent element type and a reinforcing element type, and
the core elements are arranged to a sequence so that the panel profile has a signal window in the form of at least one RF-transparent element surrounded by reinforcing elements from each side, the reinforcing elements comprising:
widthwise reinforcing elements extending along the width of the panel profile, the widthwise reinforcing elements being positioned at both lengthwise ends of each RF-transparent element, the widthwise reinforcing elements being discrete reinforcing elements which comprise at least one reinforcing material and which have a main extension in a widthwise direction; and
continuous fibres extending along the length of the panel profile, the continuous fibres being positioned on both widthwise sides of the at least one RF-transparent element and the widthwise reinforcing elements.
9 . The method according to claim 8 , wherein the method comprises
mounting the core elements on a continuous carrier in the order of the sequence, and
supplying the core elements to the pultrusion process on the carrier.