Glass antenna system for vehicles
First Claim
1. An antenna system for a vehicle having a window glass and a radio receiver, comprising:
- an antenna disposed on the window glass and having a feed point;
a matching circuit connected to said feed point; and
a coaxial cable connecting between said matching circuit and the radio receiver;
wherein said matching circuit includes a parallel circuit having a damping resistor, a first coil and a first capacitor, said matching circuit further including a second coil and a second capacitor connected in series and disposed between an output side of said parallel circuit and a ground such that, assuming that MF1 is a lower limited frequency of medium-frequency (MF) broadcast waves and MF2 is an upper limited frequency of the medium-frequency (MF) broadcast waves, a receiving sensitivity of the antenna system has local maximum points which are present at a frequency f1 in the range from (MF1-170) to MF1 KHz and at a frequency f2 in the range from (MF2-230) to MF2 KHz, respectively, and a local minimum point which is present at a frequency f0 smaller than said frequency f1 and equal to or larger than 50 KHz.
1 Assignment
0 Petitions
Accused Products
Abstract
An antenna system for a vehicle is provided. The antenna comprises an antenna disposed on a window glass and having a feed point, a matching circuit connected to the feed point, and a coaxial cable connecting between the matching circuit and the radio receiver. The matching circuit includes a parallel circuit having a damping resistor, a first coil and a first capacitor. The matching circuit further includes a second coil and a second capacitor connected in series between an output side of the parallel circuit and a ground such that, assuming that MF1 is a lower limited frequency of medium-frequency (MF) broadcast waves and MF2 is an upper limited frequency of the MF broadcast waves, a receiving sensitivity of the antenna system has local maximum points which are present at a frequency F1 in the range from (MF1-170) to MF1 KHz and at a frequency f2 in the range from (MF2-230) to MF2 KHz, respectively, and a local minimum point which is present at a frequency f0 smaller than f1 and equal to or larger than 50 KHz.
18 Citations
7 Claims
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1. An antenna system for a vehicle having a window glass and a radio receiver, comprising:
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an antenna disposed on the window glass and having a feed point; a matching circuit connected to said feed point; and a coaxial cable connecting between said matching circuit and the radio receiver; wherein said matching circuit includes a parallel circuit having a damping resistor, a first coil and a first capacitor, said matching circuit further including a second coil and a second capacitor connected in series and disposed between an output side of said parallel circuit and a ground such that, assuming that MF1 is a lower limited frequency of medium-frequency (MF) broadcast waves and MF2 is an upper limited frequency of the medium-frequency (MF) broadcast waves, a receiving sensitivity of the antenna system has local maximum points which are present at a frequency f1 in the range from (MF1-170) to MF1 KHz and at a frequency f2 in the range from (MF2-230) to MF2 KHz, respectively, and a local minimum point which is present at a frequency f0 smaller than said frequency f1 and equal to or larger than 50 KHz. - View Dependent Claims (2, 3, 4, 5)
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6. A glass antenna system for a vehicle having a window glass and a radio receiver, comprising:
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an antenna disposed on the window glass and having a feed point; a matching circuit connected to said feed point; and a coaxial cable connecting between said matching circuit and the radio receiver; wherein said matching circuit includes a first coil operative to produce a series resonance with a floating capacity between the antenna and a ground, a first resistor connected in parallel to said first coil, a second coil operative to produce a series resonance with the floating capacity between the antenna and the ground, by way of a first capacitor, a pair of a second capacitor and a second resistor connected in parallel with said second coil, and a series-parallel circuit connected between a junction of said first capacitor and said second coil and the ground, said series-parallel circuit including a parallel circuit having a third coil and a third resistor, and a third capacitor connected in series to said parallel circuit, said matching circuit further including a series circuit having a fourth coil and a fourth capacitor and connected between a junction of said second resistor and said coaxial cable and the ground such that, assuming that LF1 is a lower limited frequency of low-frequency broadcast waves, LF2 is an upper limited frequency of the low-frequency broadcast waves, MF1 is a lower limited frequency of medium-frequency broadcast waves, MF2 is an upper limited frequency of the medium-frequency broadcast waves, F0 is a frequency in the range from 50 to (LF1-20) KHz, F1 is a frequency in the range from (LF1-60) to (LF1+10) KHz, F2 is a frequency in the range from (LF2-30) to (LF2+50) KHz, F3 is a frequency in the range from (LF2+20) to (MF1-20) KHz, F4 is a frequency in the range from (MF1-130) to MF1 KHz, F5 is a frequency in the range from (MF2-230) to MF2 KHz, and F6 is a frequency in the range from MF2 to (MF2+1000) KHz, a receiving sensitivity of the antenna system has local maximum points at F1, F2, F4 and F5 and local minimum points at F0, F3 and F6, respectively. - View Dependent Claims (7)
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Specification