KR920003563B1 - Glass mounted antenna - Google Patents

Abstract

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Description

Windshield mounting antenna

1 is a front view of a preferred embodiment of the window mounting antenna of the present invention.

2 is a side view of the antenna of FIG.

3 is an ideal circuit diagram of the antenna of FIG.

4 is an ideal circuit diagram of a modified circuit for the FIG. 1 antenna.

5 is a front view of a modified embodiment of the one-piece windowpane antenna for interior installation.

6 is a side view of the antenna of FIG.

FIG. 7 is an ideal circuit diagram for the FIG. 5 antenna.

8 is a modified circuit diagram of the antenna of FIG.

FIELD OF THE INVENTION The present invention relates to antennas for transceiver devices, in particular antennas for cellular telephone frequencies, suitable for installation in window panes of vehicles.

It has long been known that antennas can be mounted on window panes and that the dielectric properties of glass can be effectively used to capacitively couple antennas to radios when the antenna and radio are on opposite sides of the window.

J. US Patent No. 1,715,952, issued June 4, 1929. a. The patent for Rostron shows a window-mounted antenna that is capacitively coupled to a transmitting or receiving device through a window.

In addition to the popularity of radios in vehicles, some early inventors patented antennas installed in windshields or windshields of vehicles. Representative of these are the patents for M Diamont of French Patent No. 1,314,455, issued December 3, 1963, and of West German Patent No. 25,393, issued April 8, 1976. L. egg. A. Patent of Eaubonne, A. of West German Patent No. 2538290, issued April 29, 1976. Seed. egg. Patents on Braggria and D. in US Pat. No. 4089817. And patents on Kirkendal.

The latest patent, issued December 9, 1980, has gained great popularity and great interest in widely used civil band radios. L. US Patent No. 4,238,799 for eight feet.

The antenna disclosed herein was a half-wavelength antenna with an electrically reduced inductive load suitable for installation on a non-conductive surface of a vehicle. Electrically scaled half-wavelength antennas have been chosen because of the unavailable ground plane, which makes the more desirable quarter-wave ground plane antenna available.

In recent years, cellular telephones have gained great popularity as accessories for automobiles. Cellular telephones are transceivers that operate in the 820 to 895 MHz frequency range. One wavelength at these frequencies is approximately one foot, thus allowing substantially any antenna length to be selected.

With the recent emphasis on style, it has been desirable to have an antenna that can be installed unobtrusively on the surface of the car without drilling holes in the body. In addition, many vehicles include large panels of non-conductive materials such as plastic and fiberglass that can be equipped with antennas. In both cases, this placement of the antenna causes the antenna to fall off the ground plane, which renders the desired antenna design unusable.

Ground antennas or antennas installed in close proximity to the ground plane have been found to improve performance in terms of radiating pattern and efficiency of the radiating element. Furthermore, the ground plane, when operated in current supply mode, improves the impedance matching characteristics of the antenna for coaxial cables connecting the antenna to the transceiver.

According to the present invention, a ground plane is generated in the antenna by adding a pair of quarter-wave stubs or a “radius” antenna at right angles to the antenna. This stub is aligned with a straight line that produces an effective “ground” plane perpendicular to the linear axis of the antenna. This main antenna is capacitively connected to the transmission line via the non-conductive surface. The stub is commonly connected to ground or a return line.

In a preferred embodiment of the present invention, the main antenna is a 5/8 wavelength segment separated by an inductive phase coil coupled with a 1/4 wavelength segment. The main antenna is installed outside the vehicle. Inside, a trimmer capacitor connected in series to the first inductor is coupled to the signal line of the coaxial cable leading to the transceiver.

The second inductor connects ground to the signal line. In a variant embodiment the ground is connected to the signal line via a second trimmer capacitor. Variants are less effective than preferred embodiments but are included for completeness.

In another variant of the invention, it has been found that a suitable antenna can be designed which can be installed entirely on a non-conductive surface, preferably on a windshield or on a front or rear windshield, inside a vehicle.

In this embodiment, the half wavelength main antenna is combined with a pair of quadrature stubs extending at right angles. As in the preferred embodiment, the main antenna is connected to the signal line through the variable capacitor and the stub is connected to the ground line. A reactive element, either an inductor or a capacitor, connects the ground and signal lines.

A more detailed description of a vehicle mobile transmit and receive communication antenna assembly constructed in accordance with the present invention disclosed herein is as follows. The kitchen device is elongated and has a first radiation section of substantially 5/8 wavelengths and extends collinearly with the second radiation section of substantially 1/4 wavelengths.

The kitchen device forms an inductance means disposed between and electrically connected with the first and second radiation sections. The first electrically conductive tuning and load member is electrically connected to the base end of the kitchen device and disposed adjacent thereto.

An electrically conductive tuning and loading member is installed on the first side of the non-conductive body portion of the vehicle. The second electrically conductive coupling member is provided on the second opposite side of the non-conductive body portion almost parallel to the first electrically conductive tuning and loading member. The first and second electrically conductive members, together with the non-conductive body portion, form a coupling capacitor at the base end of the kitchen device and are located adjacent to its current node.

The first and second radiating elements, each having a length of about 1/4 wavelength and electrically coupled to the kitchen element, form the ground plane for it. The first and second radiating elements are perpendicular to the longitudinal axis of the kitchen device. An impedance matching means having a tuning circuit tuned to the nominal resonant frequency of the capacitive load antenna is electrically connected to the second electrically conductive coupling member in close proximity to it for resonance with the kitchen element. Impedance matching means provides an impedance varying between a first impedance at connection with a second electrically conductive coupling member and between a second impedance of magnitude at least several orders of magnitude lower than the first impedance. Display. Means are also provided by the present invention for connecting the transmission line means to the impedance matching means in that the impedance of the impedance matching means is approximately equal to the impedance of the transmission line.

Other advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description with reference to the accompanying drawings in which like reference numerals refer to like members.

1 and 2, the main antenna element 12 is installed on the outside of the window 14, and the coupling and tuning circuit element 16 is installed on the inner surface of the window 14. Is shown.

Although the present invention has been shown to be installed on both sides of the pane, it will be understood that the antenna performs equally well even if the material separating the elements is any other dielectric such as a plastic panel. The present invention is ideally suitable for automobiles and can be used for windshields, backlights or any glass or plastic panel. In this preferred embodiment, only the main antenna element 12 is outside the vehicle. The remaining elements are inside which can be directly connected to the transceiver via conventional coaxial cable.

As shown in FIG. 1, the main antenna element 12 is composed of 5/8 wavelength segments 18 and 1/4 wavelength segments 20 separated by inductive phase coils 22. As shown in FIG. The main antenna element 12 is installed in the housing 24 which is pivotally coupled to the outer base member 26 which is to be attached to the surface of the window 14. A plastic cover or bezel 28 surrounds the base member 26 and exhibits only a decorative function.

The main antenna element 12 is movable in the housing and the set screw 30 fixes the antenna element 12 to an optimal length to enable limited tuning and some flexibility within the design frequency band.

The first and second stub antennas 32 and 34 extend in a direction perpendicular to a line parallel to the axis of the main antenna element 12. Each has an effective length of 1/4 wavelength. The stub antennas 32 and 34 are mounted on the inner base member 36 to be attached to the inner surface of the window 14. The inner and outer base members 36 and 26 are used as one plate of a capacitor using the glass window 14 as a dielectric element, and are therefore designed to coincide with each other when installed.

As shown in FIG. 2, the inner base member 36 includes a coaxial cable fitting to which a coaxial cable (not shown) that connects the antenna 10 to a transceiver assembly or transceiver (not shown) is fixed. When radiating, the stub antenna acts in a similar way to the ground plane, reflecting the collision energy into a desired radiation pattern. This allows the use of 5/8 and 1/4 wavelength combinations in the most effective way.

3 shows a preferred circuit in the case of using the antenna of the present invention. As shown, the main antenna element 12 is directly connected to one plate 40 of the capacitor 42 and its other plate 44 is connected to the signal terminal 48 of the coaxial cable 50 connected to the transceiver. ) Is connected via a tuning circuit 46. The glass window 14 to which the plates 40 and 44 are attached is a dielectric in the capacitor 42. An adjustable tuning capacitor 52 is connected in series to the “inner” plate 44 and can be considered as a “lump” capacitive element for circuit purposes.

In a preferred embodiment, the first inductor 54 connects the capacitors 42 and 52 in series with the signal terminal 48. The second inductor 56 connects the signal terminal 48 to the shield 54 of the ground or coaxial cable 50. The stub antennas 32 and 34 are likewise connected to the ground shield 54.

In use, the circuit is connected to the transceiver and a standing wavemeter is used with an adjustable capacitor 52 to achieve maximum performance at 820 to 895 MHz allocated to cellular mobile telephone systems.

The total capacitance (of the dielectric panel and the adjustable capacitor 52) serves to cancel the inductive reactance of the antenna.

Inductors 54 and 56 are selected to match the impedance of the antenna circuit with coaxial cable 50. Thus energy can be transferred through glass or other dielectric panels with minimal energy loss.

Since the antenna circuit is designed to operate in the current supply mode, the grounded stub antennas 32 and 34 serve as a mirror image of the main antenna 12. In the absence of a grounded stub antenna the reflected current will appear in the coaxial cable 50 and it will be difficult if not impossible to achieve good impedance matching.

In one commercially distributed version of the preferred embodiment of the present invention, the antenna system exhibits a practical standing wave ratio of 1.2: 1 or less, which exhibits very small radiation pattern distortion. The antenna has the ability to gain 3dB over the quarter-wave antenna, which is particularly useful for receiver operation.

4 is a modified circuit embodiment in which the second trimmer capacitor 62 is replaced by the second inductor 56. With this circuit, the optimal frequency range over which the circuit is tuned tends to be very sharp and narrow.

Thus, it is not as satisfactory as when dealing with a relatively wide frequency band, such as the approximately 75 MHz bandwidth available in the 800 MHz band. However, the modified embodiment is satisfactory in applications where the frequency used falls within a fairly narrow band.

5, there is shown another antenna system employing an internally mounted stub antenna in which the main antenna element is also installed inside the vehicle. In this embodiment, a single base element can be used which can be fixed on virtually any inner surface and which does not require an external mounting antenna element.

As shown, the internally mounted antenna system 110 includes a main antenna element 112, which, in the preferred version, is a half wavelength “rubber duck” that is electrically short and inductively loaded whip. Form. As in the embodiment of Figures 1 and 2, this antenna assembly also utilizes two aligned quarter-wave stub antennas 114 and 116, which consist of a “rubber duck” or an electrically shorted antenna.

As in the preferred embodiment, the stub antennas 114 and 116 are aligned at right angles to the linear axis of the main antenna element 112 to operate as a ground plane for the antenna circuit. It has long been known that grounded half-wavelength antennas can be very effective and efficient.

FIG. 6 is a side view of the antenna shown in FIG. 5 and shows how stub antennas 114 and 116 are mounted relative to the mounting surface.

7 and 8 are similar to FIGS. 3 and 4 respectively and show the overall electrical connection of the antenna assembly shown in FIGS. 5 and 6. Of course, many modifications and variations are possible within the scope of the invention as set forth above. It will be understood that all such variations and modifications are within the spirit and scope of the invention and the appended claims. It should likewise be understood to encompass all modifications and variations of the disclosed examples for purposes of illustration without departing from the spirit and scope of the invention.

Claims (18)

In the mobile transmitting and receiving communication antenna assembly 10 for a vehicle used at a UHF frequency of at least 800 MHz, which extends substantially in parallel with the first radiation section 18 having a wavelength of 5/8. The kitchen device 12 having a fourth wavelength second radiation section 20 and comprising inductance means 22 disposed between the first and second radiation sections 18 and 20 for electrical connection. ; A first electrically conductive tuning and load member 36 electrically connected to and adjacent to the base end 28 of the kitchen element 12 and installed on a first side of the non-conductive body portion 14 of the vehicle; 40); A second electroconductive coupling member 40 (the first and the first) provided on the second opposing side of the non-conductive body portion 14 disposed substantially parallel to the first electroconductive tuning and load member 36 (2) The electrically conductive members (40, 44), together with the non-conductive body portion (14), have a fixed plate surface area at the base end (28) of the kitchen element (12) and are located adjacent to the chord node thereof. A capacitor 42 is formed); Each of the first and the second having a length of substantially 1/4 wavelength and electrically connected to the kitchen device 12 to form a ground plane for the kitchen device 12 and perpendicular to the longitudinal axis of the kitchen device 12. Secondary radiating elements 32 and 34; A tuning circuit 46 tuned to the nominal resonance frequency of the capacitive load antenna to achieve resonance with the kitchen element 12, and is very close to the second electroconductive coupling member 44. A first impedance connected to the second electroconductive member 40 and substantially equal to the impedance of the base end 28 of the kitchen element 12, and at least several digits greater than the first impedance. Impedance matching means for representing an impedance varying between second impedances of low magnitude; And connecting means 38 for connecting the transmission line means 50 to the impedance matching means 36 in that the impedance of the impedance matching means is substantially equal to the impedance of the transmission line means 50. A mobile transmit and receive communication antenna assembly (10) characterized by the above-mentioned. 2. The vehicle transmitting and receiving communication antenna assembly (10) according to claim 1, wherein said impedance matching means comprises a user adjustable capacitive member (52). The method of claim 1, wherein the connection has a lower magnitude of impedance than the impedance of the antenna assembly 10 at the base end 28 of the antenna assembly for connection between the antenna assembly 10 and the wireless communication device. A vehicle transmission and reception communication antenna assembly (10) further comprising transmission line means (50). 2. The vehicle transmission and reception communication antenna assembly (10) according to claim 1, wherein said impedance matching means has a series resonant circuit (46) tuned to a nominal resonance frequency of said antenna assembly (10). The method of claim 1, wherein the base end 24 and the first electroconductive tuning and load member of the kitchen device 12 is adjusted by the user so that the kitchen device 12 is approximately perpendicular to the ground surface. A mobile transmit and receive communication antenna assembly (10), characterized in that said connection is enabled. 2. The mobile transmission and reception communication antenna assembly (10) according to claim 1, wherein the inductance means of the kitchen device (12) is composed of a spiral coil (22) formed by the kitchen device (12). . 2. The mobile transmission and reception communication antenna assembly (10) according to claim 1, wherein said non-conductive body portion (14) of said vehicle is a glass window. 2. The mobile transmission and reception communication antenna assembly (10) according to claim 1, wherein said non-conductive body portion (14) of said vehicle is a glass fiber panel. The method of claim 1, wherein the first and second secondary radiating elements (32, 34) are physically connected to the first electroconductive tuning and load member 46 and the non-conductive body portion 14 of the vehicle The vehicle transmission and reception communication antenna assembly (10), characterized in that installed on the first side. 2. The mobile transmitting and receiving communication antenna assembly (10) according to claim 1, wherein said first and second radiating elements (32,34) are approximately horizontal with respect to the ground surface. Kitchen elements 12 and 112 having at least one-half wavelength length of a desired frequency; First and second quarter wavelengths adjacent to the base 28 of the kitchen devices 12 and 112 and aligned at right angles to the kitchen device to form a ground plane, and electrically connected to a common panel; Elements 32, 34, 114 and 116; Coupling means (38) adapted to connect the kitchen device (12, 112) and the first and second quarter-wave devices (32, 34, 114, 116) to a transceiver via a coaxial cable (50); And a reactive circuit (52, 54, 56) between the kitchen devices (12, 112) and the transceiver circuit, and a tuning circuit for matching impedance between the kitchen devices (12, 112) and the coaxial cable (50). An antenna system (10,110) for a transceiver, comprising: 12. The kitchen device (12) according to claim 11, wherein the kitchen device (12) is suitable for installation on one side of the non-conductive dielectric panel (14) and the tuning and coupling means (46) is installed on opposite sides of the panel (14). Antenna system 10, characterized in that the capacitive connection with the kitchen device (12). 13. Antenna system (10) according to claim 12, characterized in that the non-conductive dielectric panel (14) is glass. 13. Antenna system (10) according to claim 12, characterized in that the first and second quarter-wave elements (32,34) are mounted on the tuning and coupling means (46). 12. An antenna system (10) according to claim 11, wherein said kitchen element (12) has a length of one-half wavelength at the kitchen frequency of the transceiver circuit. 12. Antenna system (10) according to claim 11, characterized in that the kitchen element (12) comprises a 5/8 wavelength section (18) at the kitchen frequency of the transceiver circuit. 17. The kitchen device (12) according to claim 16, characterized in that the kitchen device (12) comprises a quarter wavelength radiation section (20) separated from the 5/8 wavelength section (18) by inductive means (22). Antenna system 10. 18. Antenna system (10) according to claim 17, characterized in that the inductive means (22) consists of a helical coil formed by the kitchen element (12).

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