JP2019012960A5 - - Google Patents

Description

The capacitive loading element 12 is a metallic element that loads a resistance component and a ground capacitance to the helical element 15 that is one of the antennas, and is used together with the helical element 15 for signal reception in the AM wave band and the FM wave band. .. The capacitive loading element 12 includes two elements 121 facing each other at a predetermined interval and a predetermined angle via a virtual surface that is substantially orthogonal to the mounting surface of the vehicle roof . Each element 121 has an edge 122 whose electrical length is discontinuous. The edge 122 of the capacitive loading element 12 is arranged at a portion having a large distance from the mounting surface of the vehicle roof (not shown), and is shaped into a shape corresponding to the inner wall of the antenna case 10 in the height direction. In the present embodiment, the edge 122 is gradually increased from the front where the height of the antenna case 10 is the lowest to the rear where the height of the antenna case 10 is the highest.

In addition, since the capacitance loading element 12 has two elements 121 facing each other at a predetermined interval and a predetermined angle with respect to the virtual surface and conducts at a portion lower than the upper edge, there is no top portion and the stray capacitance is suppressed. I can . Therefore , the average gain in the FM wave band can be increased as compared with the structure having the apex. Further, since the capacitance loading element 12 is formed in a meandering shape, not only fine adjustment of the antenna characteristics becomes possible, but also positioning and engagement with the flange 111 become easy.

[Fourth Embodiment]
In the first embodiment, the example in which the DTTB connecting metal fitting 113 serving as the DTTB power feeding unit is present in front of the capacitive loading element 12 has been described. It may be located at. FIG. 16 is a schematic diagram of the antenna unit according to the fourth embodiment. The capacitive loading element 92 is the same as the capacitive loading element 12 described in the first embodiment. The DTTB element 93 of the fourth embodiment extends from the same position as the tip of the capacitive loading element 92 to the rear end of the capacitive loading element 92 when viewed in the front-rear direction, and is then bent downward. An unillustrated DTTB connection fitting (DTTB power supply portion) is arranged at the bent tip.

Claims (13)

A radio wave transmitting antenna case in which a storage space for storing the antenna parts is formed, a first antenna section and a second antenna section each composed of different antenna parts,
Equipped with
The first antenna unit includes a metal capacitive loading element extending in the front-rear direction of the storage space,
In the second antenna unit , a part or all of the antenna component overlaps the capacitive loading element in a side view ,
Antenna equipment. The first antenna unit receives at least a signal in the first frequency band,
The second antenna unit receives at least a signal in a second frequency band that is higher than the first frequency band,
The antenna device according to claim 1. The capacitance loading element is formed in a meandering shape ,
The antenna device according to claim 1 . The second antenna unit includes a radiating element including any of a linear conductor , a rod-shaped conductor, and a plate-shaped conductor,
The antenna device according to any one of claims 1 to 3. The capacitive loading element includes two elements having opposite edges at predetermined intervals,
Part or all of the radiating element is located between the edge of one of the elements and the edge of the other of the elements,
The antenna device according to claim 4 . The front of the capacitive loading element is arranged to cover the rear of the radiating element, or the rear of the capacitive loading element is arranged to cover the front of the radiating element,
The antenna device according to claim 4 . The radiating element overlaps by 0.6 times or more of the length of the capacitive loading element,
The antenna device according to claim 5 or 6 . A feeding portion of the first antenna portion is located between a front end and a rear end of the capacitive loading element,
Feeding part of the second antenna unit is positioned in the vicinity of the rear end of the front or the capacitive loading element of a front end of the capacitive loading elements,
The antenna device according to any one of claims 1 to 7 . A trap circuit that cuts off a signal in a frequency band at least receivable by the first antenna unit is connected to the power feeding unit of the second antenna unit .
The antenna device according to any one of claims 1 to 8 . The trap circuit is composed of a capacitor, an inductor, or a combination thereof .
The antenna device according to claim 9 . The first antenna section further includes a helical element, the helical element being offset with respect to the second antenna section;
The antenna device according to any one of claims 1 to 10. The first antenna unit receives at least a signal in the FM wave band,
The second antenna unit receives at least a signal in a broadcast wave band higher than the FM wave band,
The antenna device according to any one of claims 1 to 11. Further comprising an antenna base for closing the opening of the antenna case,
The antenna device according to claim 1 .