Kim Myong Il, a vice dean at the Faculty of Communications, has invented an indoor antenna for mobile communication.
Compared with previous antennas, this antenna has several advantages ― it ensures enough matching, gain and horizontal omni pattern in a wide band of frequencies; it is easy to feed, produce and assemble; it is light, good-looking and easy to install.
Consisting of a cone monopole, a double cone reflection panel, a curved plastic protection lid and coaxial feeding structure, the antenna assumes horizontal omni pattern in a wide range of frequency such as GSM, WCDMA, LTE, etc. With the gain of 3dBi, it can provide indoor mobile communication service in areas such as the underground of a building where mobile communication service cannot reach.
As a wide-range radiator, a cone monopole has top and bottom panels made of metal (Oblique angle is 25.5, radii are 12mm and 21mm respectively.), with an impedance of 50Ω and a wide radiation area. So it is of nearly omni directional pattern on the horizontal plane.
Vertical radiation can be controlled by a double cone reflection panel consisting of a primary cone reflection panel, a plain reflection panel, an upper cone reflection panel for coaxial feeding and it can bring a gain of 3dBi.
The inner conductor of a feeding coaxial cable is connected to the bottom panel and the outer conductor is linked to the reflection panel. The impedance of the antenna can be controlled by inserting an inclined line between the cone monopole and the reflection panel. Therefore, the impedance of the antenna remains constant in a wide frequency range. What is more, it is easy to install on the wall and it is covered tightly with a radome made of glass fiber plastic in order to prolong the life span and give a good-looking appearance.
In a wider frequency range(756~1 063/1 670~2 777MHz) than in the frequency range of former wire monopoles, the gain is 3.2dBi, which is 1.1dBi higher than former antennas (2.1dBi), so the service bound gets 1.4 times wider than before. The antenna is light, easy to install and meets aesthetic requirements.
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