SE504343C2

SE504343C2 - Ground plane adapter for temporarily connecting a detached antenna with a coaxial cable to a mobile telephone associated with the antenna

Info

Publication number: SE504343C2
Application number: SE9504018A
Authority: SE
Inventors: Ina Ericsson
Original assignee: Allgon Ab
Priority date: 1995-11-13
Filing date: 1995-11-13
Publication date: 1997-01-20
Also published as: WO1997019489A1; SE9504018D0; AU7714196A; SE9504018L

Abstract

In order to connect an outside antenna with the antenna of a portable telephone by a coaxial cable, a connector is used, which includes a ground plane. The connection is established by a capacitive coupling between an active member being joined with the cable and the antenna of the portable telephone. In order to increase the capacitive coupling between the antenna and the active member, the active member is formed as a quarter wave antenna consisting of two eighth wave length antennas having a common feeding point. Close to the antenna of the telephone there is a metal plate and above it there is a coil forming an angle with the metal plate. These two members forming said quarter wave antenna. The size of the coil and the metal plate are related to the frequency band of the telephone.

Description

15 20 25 30 35 504 343 Ritningsfiguren l visar starkt förenklat övre delen av en mobil telefon 1 med tillhörande antenndel 2 och adapter. 15 20 25 30 35 504 343 The drawing figure 1 shows in a greatly simplified manner the upper part of a mobile telephone 1 with associated antenna part 2 and adapter.

Telefonen l har på sin ovansida en helixantenn 2, eventuellt är denna helixantenn kmpletterad med en utdragbar ståndarantenn.The telephone 1 has on its upper side a helix antenna 2, possibly this helix antenna is supplemented with a extendable stand antenna.

Den till telefonen förenade antennen i form av helixantennen 2 och/eller ståndarantenn förutsättes fungera tillfredsställande när telefonen med tillhörande antenn ej befinner sig på avskärmad plats. På avskärmad plats behöver antennen förstärkning i form av en utanför avskärmat område belägen antenn som lösbart kan anslutas till den befintliga antennen på telefonen.The antenna connected to the telephone in the form of the helical antenna 2 and / or upright antenna is assumed to function satisfactorily when the telephone with the associated antenna is not in a shielded place. In the shielded location, the antenna needs amplification in the form of an antenna located outside the shielded area that can be releasably connected to the existing antenna on the telephone.

Nämnda ytterligare antenn betecknas i ritningsfiguren med 3 och befinner sig således på avstånd från telefonen l. En antennledning 4 i form av en koaxialkabel från antennen 3 är förenad med ett aktivt element 5 i adaptern.Said further antenna is indicated in the drawing figure by 3 and is thus at a distance from the telephone 1. An antenna line 4 in the form of a coaxial cable from the antenna 3 is connected to an active element 5 in the adapter.

Det aktiva elementet 5 utgör den kopplingsverksamma delen av adaptern och kan lösbart förläggas intill antennen 2 så att kapacitiv koppling sker mellan aktiva elementet 5 och antennen 2. Således kommer signaler intagna av antennen 3 att tillföras helixantennen 2, via koaxialkabeln 4 samt adaptern. Utsändning av signaler sker i andra riktningen.The active element 5 forms the coupling-active part of the adapter and can be releasably placed next to the antenna 2 so that capacitive coupling takes place between the active element 5 and the antenna 2. Thus, signals received by the antenna 3 will be applied to the helix antenna 2, via the coaxial cable 4 and the adapter. Transmission of signals takes place in the other direction.

Adaptern innefattar vidare ett litet jordplan 6, som har ett plan 7 uppbärande det aktiva elementet 5 och är galvaniskt förenat med koaxialkabelns 4 skärm. Vidare sträcker sig i vinkel nedåt från planet 7 ett andra plan 8. Vid adapterns användning kommer planen 7 och 8 att bli förlagda mot eller nära telefonens ovansida 9 respektive ena utsida 10.The adapter further comprises a small ground plane 6, which has a plane 7 supporting the active element 5 and is galvanically connected to the shield of the coaxial cable 4. Furthermore, a second plane 8 extends at an angle downwards from the plane 7. When the adapter is used, the planes 7 and 8 will be located towards or near the upper side 9 and one outer side 10 of the telephone, respectively.

Företrädesvis har adaptern också ett hölje ll av elektriskt oledande material.Preferably, the adapter also has a housing 11 of electrically non-conductive material.

Man har funnit att kopplingen mellan antennen 2 och det aktiva elementet 5 är känslig och bör optimeras. Särskilt gäller detta vid höga frekvenser, 1,5 GHz och uppåt. Enligt uppfinningen optimeras denna koppling genom att det aktiva elementet utgörs 10 15 20 25 30 35 3504 343 av en mittmatad kvartvågsantenn eller snarare två stycken åttondelsvåglängdsantenner med gemensam matningspunkt. Den så bildade kvartvågsantennen består av en metallskiva 12 bidragande med huvuddelen av den kapacitiva kopplingen närmast jordplanet och ovanför detta en mot metallskivan 12 vinklad spole 13 som ger kvartvågsantennen en impedans motsvarande koaxialkabelns, t.ex. 50 Q. Metallskivan 12 är ca en åttondels våglängd hög och dess bredd anpassas till önskad kopplingseffekt.It has been found that the connection between the antenna 2 and the active element 5 is sensitive and should be optimized. This is especially true at high frequencies, 1.5 GHz and up. According to the invention, this connection is optimized in that the active element consists of a mid-fed quarter-wave antenna or rather two eighth-wavelength antennas with a common feed point. The quarter-wave antenna thus formed consists of a metal plate 12 contributing with the main part of the capacitive coupling closest to the ground plane and above this a coil 13 angled towards the metal plate 12 which gives the quarter-wave antenna an impedance corresponding to the coaxial cable, e.g. 50 Q. The metal plate 12 is about one-eighth of a wavelength high and its width is adapted to the desired coupling effect.

Spolen 13 har en längd som motsvarar ca en åttondels våglängd.The coil 13 has a length corresponding to about one-eighth wavelength.

Trådtjockleken anpassas efter önskad bandbredd. Denna spole 13 fungerar, utöver dess antennfunktion, som en induktans som kompenserar metallskivans 12 kapacitans. Induktansvärdet ges av stigningen och diametern, och anpassas till aktuellt frekvensområde. Även spolens 13 lutning, i förhållande till metallplattan 12 och jordplanet 7, påverkar dess induktansvärde och anpassas till önskad koppling till antenn 2 och önskad induktans till jordplan 7. Spolen kan ersättas av annan komponent, som ger önskad induktans och koppling till antenn, t.ex. en spiralslinga såsom visas i fig. 4-6.The wire thickness is adjusted to the desired bandwidth. This coil 13 functions, in addition to its antenna function, as an inductance which compensates for the capacitance of the metal plate 12. The inductance value is given by the pitch and diameter, and is adapted to the current frequency range. The inclination of the coil 13, relative to the metal plate 12 and the ground plane 7, also affects its inductance value and is adapted to the desired connection to antenna 2 and the desired inductance to ground plane 7. The coil can be replaced by another component which provides the desired inductance and connection to antenna, t. ex. a spiral loop as shown in Figs. 4-6.

Fig. 4-6 visar samma som fig. 1-3, men övre delen av kvartvågsantennen är av annan form. Således utgörs den här av en metallslinga 14. Denna slinga har samma funktion som spole 13. Slingans största ytterdiameter är ca en kvarts våglängs.Figs. 4-6 show the same as Figs. 1-3, but the upper part of the quarter-wave antenna is of a different shape. Thus, this consists of a metal loop 14. This loop has the same function as coil 13. The largest outer diameter of the loop is about a quarter of a wavelength.

Trådtjockleken anpassas efter önskad bandbredd, men begränsas av önskat avstånd mellan varven. Induktansvärdet ges av den mindre av ytterdiametrarna och avstånd mellan varven. Även slingans 14 vridning gentemot ett plan parallellt med jordplanet 7 och dess lutning i förhållande till samma plan, påverkar dess induktans och anpasss till önskad koppling till antenn 2 och önskad induktans till jodplan 7. Adaptern enligt detta utförande är i övrigt lik den enligt fig. 1-3, varför samma hänvisningssiffror ingår.The wire thickness is adapted to the desired bandwidth, but is limited by the desired distance between the turns. The inductance value is given by the smaller of the outer diameters and the distance between the turns. The rotation of the loop 14 towards a plane parallel to the ground plane 7 and its inclination in relation to the same plane also affects its inductance and is adapted to the desired connection to antenna 2 and desired inductance to iodine plane 7. The adapter according to this embodiment is otherwise similar to that of fig. 1-3, why the same reference numerals are included.

Claims

10 15 20 25 30 35 504 3434 PATENT REQUIREMENTS

A ground plane adapter for temporarily connecting a free-standing antenna to a mobile telephone antenna with a coaxial cable, the connection taking place by means of a capacitive connection between the telephone antenna and an active known element connected to the coaxial cable, knowing that the active element consists of two eighths wavelength antennas (12, 13; 14) with common feed point, where one (12) mainly forms a capacitive coupling component with the telephone antenna and the (13: 14) components are connected at the feed point. others are in the form of an inductive component, which means that the capacitively coupling component consists of a metal plate

An adapter according to claim 1, characterized by (12) one-eighth wavelength. k ä n n e t e c k n a d (13; 14)

An adapter according to claim 1, wherein the inductive component

Adapter according to claim 3, characterized in that the inductive component consists of a helical coil aV, (13), the center axis of which forms an angle with the longitudinal direction of the capacitive coupling component (12).

5. An adapter according to claim 3, characterized in that the inductive component is constituted by a spiral loop (14), the plane of which forms an angle with the longitudinal direction of the capacitive (12). HV, coupling component

Adapter according to one of the preceding claims, characterized in that the adapter has a ground plane in the form of a plate (7), connecting the component which is extended perpendicular to the longitudinal capacitive (12) direction. is of eighth wavelength.