A circuit substrate with a coil

Abstract

The invention provides a circuit substrate (1) with a coil, which is provided with more than three wiring layers (11, 12, 13, and 14). Among the wiring layers, at least the wiring layer (11) on the front side and the wiring layer (12) closely above form coil patterns (21, 22), and the coil patterns (21, 22) are electrically connected through a conductor (23). The wiring layer (14) on the front side of the circuit substrate (1) is free from coil pattern. The coil patterns (21, 22) are tilted in the front-sided structure of the circuit substrate (1); and the coil patterns (21, 22) formed on the wiring layers (11, 12) is 1mm or less in thickness. Accordingly, the structure is applicable to transmitting high-frequency signal.

Description

technical field [0001] The invention relates to a circuit substrate with a coil. Background technique [0002] In recent years, circuit boards incorporating coils have been known. For example, a high-frequency amplifier circuit is known in which a coil constituting an amplification stage and a coil constituting a filter stage are built in a multilayer circuit board (for example, refer to Patent Document 1). In addition, there is known a substrate inner-layer coil in which two coil patterns of the same shape are embedded in a substrate main body, and the two coil patterns are sandwiched between a first ground electrode layer and a second ground electrode layer (for example, refer to Patent Document 2 ). On the other hand, among the electronic cards that perform data communication with a reading device or a writing device, etc. in a non-contact manner, an electronic card is known in which a card is formed on an upper cover and a lower cover of a case respectively. There is ...

AI Technical Summary

Problems solved by technology

However, in that case, the strength of the substrate is lowered, and warping (reverse ri) tends to occur on the substrate, so that, for example, problems may occur in a solder reflow process during manufacture.

In addition, in the electronic card disclosed in Patent Document 3, the portion of the communication coil pattern formed on the cover on the side farther from the coil of the communication partner is separated from the coil of the communication partner by the thickness of the card. Has difficulty transmitting high-frequency signals

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