公开(公告)号：GB2415544A

公开(公告)日：2005-12-28

申请号：GB0414231

申请日：2004-06-25

Applicant: MOTOROLA INC

Inventor： ZEHNGUT IIAN ,  GROSSMAN OVADIA ,  SLOTIN HAIM

IPC: G08C17/02 ,  H01Q1/04 ,  H01Q1/22 ,  H01Q25/00

Abstract: A radio frequency (RF) communication device 100 and a method of its operation or construction comprise an antenna 102 with an elongate member having first 107, second 108 and third 112 portions. All of the said portions 107, 108, 112 have a common first conductor 109. The first and second portions 107, 108 have second conductors 111 arranged parallel to the first conductor 109 with insulating material 110 between the first and second conductors and the said second conductors are isolated from one another. The antenna 102 is attached to a transmitter 106 and may be formed by a flexible coaxial cable with a slot in the outer conductor. The device may be used for a meter located in a pit. The transmitter 106 may be arranged with the antenna 102 extending down or up from the transmitter with the transmitter mounted in a perpendicular manner to the lid of the pit. The antenna 102 may include said first, second and third portions in a linear section of the antenna. A further loading and radiating portion in the form of a coil may extend from the linear section and may be formed as a result of insertion into a support structure. The further coil portion is formed in a plane parallel to that of the pit lid and perpendicular to the linear section of the antenna. The antenna arrangement may operate in either or both horizontal and vertical polarizations and may be arranged close to ground level to avoid unwanted ground reflections. The length of the second and third portions may equal that of the first portion combined with the length of the transmitter casing 101 and may be equivalent to a quarter wavelength of the radiation to be emitted.