SE513022C2 - Dielectric material for microwaves - Google Patents

Abstract

A laminate construction for use in microwave electronics, such as for circuit boards or antennas, has expensive dielectric material having a low dissipation factor (Df < 0.005 at 1 GHz), such as PTFE/glass or Gore-ply3, only in the upper 200 mu m and less expensive dielectric material having a higher dissipation factor (Df > 0.005 at 1 GHz), such as FR-4, cyanate ester, BT/epoxy, polyimide thermount or polyimide, in the underlying 400 mu m of the dielectric material, thereby reducing cost while maintaining the same performance as regards low energy loss and consistency of the dielectric constant over the temperature and frequency range of use.

Description

. ___. mainly low heat generation and low variation in the dielectric constant. This is especially desirable for antennas that use significant amounts of material, such as those used in the new GSM 1.8 system. Tests on which the present invention is based have shown that for a frequency of 1 GHz only the top 200 μm of the card needs to be of top quality in terms of its output, and the remaining underlying part may be of inferior quality and thus reduce the total cost of the larnate.

Another object of the present invention is to provide a method of manufacturing such a component carrier or antenna.

Brief description of the drawings The figure schematically shows a composite microwave card.

Detailed description of embodiments The figure shows an embodiment of the heating, which is a composite mile-wave card. On a ground plane 1, a lower layer 2 of a cheaper dielectric material is applied, which in this case is a liR-4 material. It is also possible to use materials which have a attenuation factor at 1 GHz greater than 0.005 within the range of the invention, for example cyanate ester, BT / epoxy, polyimide thermount or polyimide. On this lower 2, an upper layer 3 of higher quality material, such as PTFE / glass or Gfpre-ply®, is applied. This upper layer 3 has an attenuation factor Df at 1 GHz which is less than 0.005.

Däinpfaldorn Df is used: as a measure of the energy loss (heat) in relation to - energy stored at a certain microwave frequency (in this case 1 GHz). This attenuation factor 1 can be expressed as tan δ, where δ is the angle formed by the vector components e 'and e ", where e' is a real component corresponding to the stored energy and e" is an engineering component that corresponds to the energy emitted, called the loss factor. In a vector diagram, e 'and e' are shown phase-shifted 90 °, and thus the relationship between them can be termed tan δ, where δ is the angle formed by the two vectors.

In the method according to the invention, a lower layer 2 of cheaper dielectric material with a high damping factor (Df> 0.005) is laid on a ground plane. This lower layer may have a thickness of 400 μm of a total dielectric thickness of 600 μm. An upper layer 3 (approx. 200 μm) of a more expensive dielectric material (Df <0.005) is then laid on the lower layer 2. A conductive layer 4 is laid there on the upper layer 3. Electronic components can be mounted on the conductive layer 4 .

Claims (3)

5 15 20 25 513 022 4 A laminate structure: for applications in microwave electronics, comprising: at least one ground plane (1), a lower layer (2) of dielectric material with a attenuation factor Df at 1 GHz, greater than 0.005, laid on said ground plane, an upper layer (3) of dielectric material with a attenuation factor Df at 1 GHz, which is less than 0.005, me: on the: lower layer, a conductive layer (4), optionally comprising electronic components, mounted on said upper. Laminate construction according to claim 1, wherein the upper layer (3) of dielectric material is approximately 20 μm thick. . A laminate structure according to claim 1 or 2, wherein said laminate structure is a circuit board. . Laminate construction according to claim 1 or 2, wherein said laminate construction 1 is an antenna. . A method of making a laminate construction according to any one of the preceding claims, comprising the following steps: Laying on a ground plane (1) a lower layer (2) of dielectric material with an attenuation factor Df at 1 GHz greater than 0.005, 2. where the lower layer (2) is laid, an upper layer (3) of dielectric material with a attenuation factor Df at 1 GHz of less than 0,005 is applied to said lower layer (2), 3. after which said upper layer (3) is laid a conductive layer (4).