Field of the Invention
The present invention relates to a chip antenna with a ground installed that can be widely used for wireless LAN, Bluetooth, cell phones, and the like; and a communication circuit substrate for transmission and reception that has the chip antenna installed.
Description of Related Art
Recently, as electronic devices are being reduced in size to improve portability, more and more electronic devices are being mounted with wireless capabilities (wireless LAN, Bluetooth, and the like) to communicate with such electronic devices. As a result, the demand for an antenna mounted on the communication circuit substrate for transmission and reception of an electronic device that occupies a smaller area within the circuit substrate is rising.
With this kind of demand, a reduction in the size of the antenna device is desired. This is the background to why chip antennas including the one disclosed in Japanese Patent Application Laid-Open Publication No. 2011-101232 (Patent Document 1) have been developed. This kind of antenna device inhibits the reduction in size of the antenna device because the possible layout of the substrate components is limited because the ground electrode of the substrate in the portion where the antenna device is mounted needs to be removed in order to express the characteristics of the antenna device.
Also, if a radiating electrode is arranged so as to be parallel to a ground electrode, the magnetic field generated by the radiating electrode enters the ground electrode and generates an induction current. The effect of the magnetic field generated by the induction current cancels the current flowing into the radiating electrode and dissipates the current as heat. The resulting problem is that the performance of the antenna deteriorates unless there is enough distance between the radiating electrode and the ground electrode.
The invention disclosed in Japanese Patent Application Laid-Open Publication No. 3114582 (Patent Document 2) was invented to solve such a problem. The chip antenna in this invention can be mounted on the ground electrode and thus contribute to the size reduction. Specifically, this is an antenna device in which the tip of the excitation electrode and the open end of the radiating electrode formed so as to be parallel to the ground electrode is capacitively coupled at a gap, and a terminal side of the radiating electrode is connected to the ground electrode.