Transmitting and receiving arrangement for portable appliances.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a transmitting and / or receiving arrangement for portable devices, comprising a shielding housing of metal and an antenna which contains the high-frequency part, the antenna comprising two or more antenna resonators which are radiated together and essentially identically in the longitudinal direction and each have a free resonator end and In each case an angled edge which is angled over a bending edge and conductively connected to the shielding housing.

EP-A 177 362 describes a broadband antenna for portable radios. It consists of two angled resonators of different resonant frequencies. Both resonators are fed from a common line via a branch in the manner of an "inverted-F antenna". The antenna resonators act independently and do not form a unit. Therefore, the efficiency is not particularly large. The distance between the parallel legs is constant.

US Pat. No. 4,584,585 describes an antenna with resonators made of wire angles. A resonator is fed at the end and forms an "inverted-L antenna". The second resonator is radiation-coupled. Although this arrangement achieves good efficiency, the antenna has a fixed impedance and is poorly adaptable. The shape of the active antenna resonator is relatively difficult to bend, and the base plate also has a step. The bandwidth is relatively low.

GB-A 2 067 842 describes a microstrip antenna which is applied to an insulating mass. Here, too, the distance between the two antenna resonators is constant. The resonators lie opposite one another with the free ends. The feed point is close to the free end of a resonator. *** "" Inverted F antennas are known from T. Taga and K. Tsunekawa, \ "Performance Analysis of a Built-In Planar Inverted F Antenna for 800MHz Band Portable Radio Units, \" IEEE Trans., Selected Areas in Commun. Vol. SAC-5, no.5, pp. 921-929, June (1987). An adaptation of such antennas is effected by varying the position of the feed point.

The invention is based on the object of improving the transmitting and receiving power of the antenna, whereby a simple fabrication and good adaptability is to be ensured with a large bandwidth.

According to claim 1, this is achieved by means of a transmitting and / or receiving arrangement for portable devices, consisting of a shielding housing of metal and an antenna containing the high-frequency part, the antenna being composed of two or more antenna resonators which are identically oriented in the longitudinal direction and each have a radiation resonator Free resonator end and in each case an end which is angled over a bending edge and conductively connected to the shielding housing, wherein the transmitter output or receiver input, if necessary via a duplex filter, is connected by a coaxial feedthrough in the shielding housing via a feed line only to the feed point of a single antenna resonator And wherein, for varying the input impedance of the antenna, the clear width of the slot formed between two adjacent antenna resonators is considerably smaller in the region of the free resonator end than at the kink edge.

The non-fed resonators of the antenna are excited by the fed resonator in a radiation-coupled manner, as a result of which the bandwidth of the antenna is increased. Due to the angled shape and the broadening of the ends, currents flow in all three spatial directions. High cross currents are formed, which cause a small impedance. Gaps are filled in the directional characteristic of the antenna. Due to the low space requirement, the arrangement is ideally suited for mobile radio applications. It is easy to manufacture and the entire high-frequency, low-frequency and digital electronics of a portable radio can be accommodated in the shielding housing. The metal housing also serves as a ground simulator for the antenna. By changing the attachment point of the feed line to the antenna resonator and by varying the input impedance of the antenna, the resonators are widened in the region of their ends, the range of variation is particularly large. Therefore, adaptation networks between the antenna and the transmitting end stage or transmission filter, as well as between the antenna and the receiving input or receiving filter, can be saved in many applications. The arrangement of the mutually substantially parallel antenna resonators can also be described as a slot antenna, the input impedance being variable within wide limits by the width and shape of the slot between the resonators.

The object can be achieved according to patent claim 2 by means of a transmitting and receiving arrangement for portable devices, consisting of a shielding housing of metal and an antenna containing the high-frequency part, wherein the antenna consists of two or more antennas resonators which are identically oriented in the longitudinal direction, A free resonator end and in each case an end which is angled over a bending edge and conductively connected to the shielding housing, the transmitter output and the receiving input being in each case connected via a transmitting filter or receiving filter through a coaxial feedthrough in the shielding housing via a respective feed line to the feed point of another antenna resonator , Which feed point lies in each case between the kink edge and the free resonator end of the respective antenna resonator, and wherein the clear width of the slot formed between two adjacent antenna resonators in the region of the free resonator end is considerably smaller for the purpose of varying the input impedance of the antenna than at the kinking edge.

Among the advantages of the arrangement according to claim 1, a partial decoupling of the transmitter output and the receiver input is achieved by the supply of two antenna resonators and the connection of the feed lines to the transmitting and receiving filters. Furthermore, a separate optimization of transmitter and receiver adaptation is possible.

The antenna can, in principle, be located above any desired side surface of the shielding housing. In tests, however, it has proved to be advantageous for the antenna resonators to be arranged on the upper side or cover surface of the screening housing. For a diversity operation, the antenna is composed of at least two fed, mutually opposing subantennas, each of which consists of the two or more radiation-coupled and essentially identically oriented antenna resonators (FIG. 4). Both sub-antennas can be of the same length, resulting in double resonance. The antenna consists of Lambda / 4 resonators. Therefore, the bandwidth can be further increased when the length of the antenna resonators is unequal.

A reliable mechanical design is achieved in that the angled antenna resonators are formed from sheet metal angles. In order to improve the radiation characteristics, it is advantageous that three sheet metal angles are present and the middle sheet angle is connected to the supply line. To produce the metal parts in a single operation, it is advantageous that the shielding housing and the sheet metal angle are punched out of a flat sheet and bent into the corresponding shape. However, it is also possible for the sheet metal angles to be soldered onto the shielding housing.

The mechanical loadability of the antenna is increased by the fact that the sheet metal angles have a U-shaped long section and the non-fed or non-radiation-coupled leg is conductively attached to a circuit board protruding from the shielding housing and is connected to the shielding housing via a ground surface. A particular stiffness is achieved in that the circuit board projects between the free resonator ends of the sheet metal angle and the resonator ends are connected to the circuit board. By means of these measures, the antenna can be integrated on the circuit board.

A particular mechanical resistance is provided in that the shielding housing is surrounded by a plastic housing on which the sheet metal angles are applied as a metal foil on the outside or inside and are connected to the shielding housing via a mass feedthrough.

Moreover, it is also advantageous that the angled antenna resonators are formed from wire angles. These wire angles converge towards each other in such a way that their free resonator ends are only slightly distant from each other. High currents also flow here and a small impedance results. The "Inverted-F" structure has the advantage over the inverted-L structure of a higher quality of the adaptation to the broadband. The improvement is about 50-100%.

The invention is explained in more detail by means of several exemplary embodiments and from drawings. Show it:<ul><li>1 shows an example with two sheet metal angles, FIG.</li><li>FIG. 2 shows the plan view with the antenna region,</li><li>FIG. 3 shows an example with two supply lines,</li><li>FIG. 4 shows an example with two sub-antennas,</li><li>FIG. 5 shows an example with three antenna resonators,</li><li>FIG. 6 shows an example of integration on a circuit board,</li><li>7 shows an example with resonators made of metal foil and FIG</li><li>FIG. 8 shows an example with resonators of wire angles.</li></ul>

In the following exemplary embodiments, antennas with two or more angled resonators are described, which can be installed in portable radios, such as cordless telephones, mobile telephones, pagers, "telepoint devices", etc. As an internal antenna for a digital cordless telephone, it is set to the 1.7 GHz band. The common functional features are generally indicated only in the first exemplary embodiment.

The construction of a first antenna is shown in FIG. On a shielding housing 1, the two sheet angles 2, 3 acting as an antenna are mounted on the upper side. The shielding housing 1 contains the entire high-frequency, low-frequency and digital electronics of the handset of a cordless telephone.

Apart from the shielding, the shielding housing 1 also fulfills the function of a ground simulation for the antenna and influences the bandwidth. The larger it is, the smaller the bandwidth. The upper side of the shielding housing 1 has proved to be a favorable location for the attachment of the antenna.

The shielding housing 1 (or parts thereof) and the sheet metal angle 2, 3 are punched out of a flat sheet metal and bent as shown in FIG. Connected to the first sheet metal angle 2 is a feed line 4, which leads out of the interior of the screening housing 1 via a coaxial feedthrough 5. The first sheet metal angle 2 is thus the fed element of the antenna, the second sheet angle 3 is radiation-coupled to the first sheet angle 2. The supply line 4 is connected inside the shielding housing 1 via a duplex filter to a receiver input or transmitter output.

2 shows the mounting point of the feed line 4 at the first sheet metal angle 2. The location of this mounting point and the shaping of the mutually facing edges of the sheet metal angle 2. 3 makes it possible to vary the input impedance of the antenna over a wide range. The sheet metal angles 2, 3 are widened towards the ends. This saves a matching network between the antenna and the transmitter output or receiver input. The two plate angles 2, 3 have a different length. Due to the resulting different resonant frequencies of the individual radiators, a considerable increase in the bandwidth results compared to a comparable antenna consisting of a single sheet angle.

An alternative possibility of connecting transmitter and receiver with the antenna according to the invention is shown in FIG. The first sheet metal angle 2 is connected to the first supply line 4, the second sheet metal angle 3 is connected to a second supply line 6. The supply lines 4, 6 are led out through feedthroughs 5. The transmitter output is connected to the first sheet angle 2 via a transmission filter. Correspondingly, the receiver input is connected to the second sheet angle 3 via a reception filter. This type of embodiment results in a part of the required decoupling of the transmitter output and the receiver input. The variation of the input impedance by shaping of the sheet metal angles 2, 3 and variation of the fastening point of the feed lines 4, 6 takes place as in the first exemplary embodiment.

FIG. 4 shows an antenna arrangement for diversity operation. Two partial antennas are arranged on the narrow side of the shielding housing 1. The first partial antenna consists of the first two sheet metal angles 2, 3. The second partial antenna is constructed identically and consists of sheet metal angles 7, 8. The feed for the first subantenna is via the feed line 4 through a coaxial feedthrough 5, and the second subantenn is correspondingly applied. The length of the resonators is lambda / 4. Both sub-antennas are of equal length and double resonance occurs.

In the case of the transmitting and receiving arrangement shown in FIG. 5, a third sheet angle 9 is arranged between the two sheet metal angles 2, 3 from the shielding housing 1. The free resonator end of the third sheet angle 9 is widened symmetrically towards the first two sheet metal angles 2, 3. The feed line 4 is connected to the third sheet angle 9 via the coaxial feedthrough 5. The two first sheet metal angles 2, 3 are radiation-coupled.

In the example according to FIG. 6, the shielding housing 1 consists of two parts and encloses a circuit board 12 on which the components of the device are arranged. The printed circuit board 12 protrudes on the upper narrow side between the parts of the shielding housing 1 and is provided with a grounding surface 14. The antenna consists of sheet metal angles 10, 11, which have a U-shaped longitudinal section. They are connected to the ground surface 14 by a soldering point 13 over the entire length of the respective lower limb of the sheet metal brackets 10, 11 and are fastened to the circuit board 12. The feed is effected via a conductor track through the feedthrough 5 in the shielding housing 1 and a recess in the lower limb of the sheet metal angle 10 to the feed point 15. Again, the sheet metal angle 10 is connected to the plate 12. If necessary, the free resonator end can also be connected to the circuit board 12. Both separate and common feeding of the sheet metal angles 10, 11 is possible.

In another example according to FIG. 7, the shielding housing 1 is surrounded by a plastic housing 16. The plate angle 2.3 are outside the Kun sprayed ststoffgehäuse 16th It would also be possible to etch them out. The sheet angle 2 is connected to the transmitter / receiver from a feed point 17. The contact of the sheet metal angle 2, 3 with the shielding housing 1 is produced via a mass feedthrough 18.

The antenna of the transmitting and receiving arrangement according to FIG. 8 is made of wire angles 19, 20. They converge towards each other and are only slightly separated from one another at the free resonator end. The wire angles 19, 20 are soldered to the shielding housing 1, and the second wire angle is connected to the transmitter / receiver via a supply line 4. For this purpose, the shielding housing 1 has a coaxial feedthrough 5. These wire angles 19, 20 are designed to be stretched and therefore have a simple shape. The shielding housing 1 has no step.