This invention concerns means for filter effect by antennas fo communication radio sets and wireless telephones having the transmitter and the receiver in one and the same housing, to which an antenna is adapted and forms communication means for signales to and from another apparatus.

The object of the invention is to eliminate the necessaty of a duplex filter which is adapted in the apparatus in order to protect that the transmitting signal disturbes the receiver in communication radio set or a wireless telephone. Duplex filter is an expensive means and it is a great advantages if the antenna can be arranged without duplex filter.

In order to achieve the above stated object the invention is characterized in that the antennas are adapted separated from each other whereby one of the antennas is connected to and tu to the transmitter and the second antenna is connected to and tuned to the receiver.

The invention will be described in two embodiments with reference to the enclosed drawings.

Fig. 1 is thereby a schematic view of an apparatus having externel antennas.

Fig. 2 is a schematic view of a similar apparatus but having antennas inside the housing.

Fig. 3 is a view of an antenna to be used with the apparatus according to Fig. 2.

A communication radio set or a wireless telephone includes a housing 1. A receiver 2 and a transmitter 3 are arranged

SUBSTITUTE SHEET

within the housing. The apparatus is so formed that the communi¬ cation operates ^*" "in and out at the same time and thus without either of the receiver or the transmitter to be turned off. The apparatus is provided with a first antenna 4 which is connected to the receiver and a second antenna 5 which is connected to the transmitter. The transmitter and the receiver operate on different frequences. Preferably the antenna 4 is tuned to the receiver 2 and the antenna 5 is tuned to the transmitter 3. The antenna 4 may be connected to the receiver via a simple filter 6 and the antenna ^" 5 may be connected to the transmitter 3 via a simple filter 7. Duplex filter, which is much more expensive than the filter ^' s 6 and 7 is not needed when operating the apparatus according to Fig. 1.

A second embodiment is showen in Fig. 2 and it can be seen that in this case the antennas 8 and 9 have been placed inside the housing 1. Simple filters 10 and 11 may also in this case be placed between the connections to the antennas respectively. When using the embodiment according to Fig. 2 it is preferable that the antennas θ and 9 are so formed that the aerial pattern is asymmetrical, thus according to the patterns showen on the left side of Fig. 2. The antenna action will thus be directed from the interior of the apparatus. By this type of antenna, which can be said to have directive action, are further reduced the requirements of the preformens of the filters 10 and 11. Further the radiation inwardly to the units which are placed inside the apparatuses, is reduced and the electrical misfunction of these units is eliminated or at least reduced.

Antennas having a radiation action according to what is showen in Fig. 2 can be designed also according to the antennas showen in Fig. 1.

Using the antenna system which now have been described will mean that the connections between antenna and receiver respectively

can be made more simple. The contacts of the antennas can simply be of the coaxial type or any other type which are availible on the market and using this simple types of contacts will make the design simple and cheap.

An embodiment of an antenna which has directive action is showen schematicly in Fig. 3. The antenna according Fig. 3 can be said to represent the antenna 8 Fig. 2 and it consists of a metal element 12 and antenna elements 13 placed above the metal element 12. The antenna pattern of this antenna is according to the diagram in Fig. 2 at the top to the left. This diagram is the denoted with A.

A design perporming the antenna pattern according to B of Fig. 2 can be used for the antenna 9. The antenna showen in Fig. 3 is here by inverted.