WO2014118189A1

WO2014118189A1 - Antenna device and site installation for mobile radio communication

Info

Publication number: WO2014118189A1
Application number: PCT/EP2014/051646
Authority: WO
Inventors: Martin Schwab
Original assignee: Martin Schwab
Priority date: 2013-01-29
Filing date: 2014-01-28
Publication date: 2014-08-07
Also published as: DE102013201432A1

Abstract

An antenna device for a site installation for mobile radio communication includes at least one receiving path having at least one tunable receiver antenna element (113a-113c) for receiving a mobile radio communication signal and at least one tunable receiver filter (111) for filtering the signal from the least one tunable antenna element, wherein the receiver path has a bandwidth which is at least as great as the bandwidth of a receiving channel (rxch), but smaller than the bandwidth of the receiving band (rx), and/or at least one transmitter path having at least one tunable transmitter filter (211) for suppressing unwanted signals outside of the transmitting band and at least one tunable transmitter antenna element (213a-213c) for emitting a mobile radio communication signal, wherein the transmitter path has a bandwidth which is at least as great as the bandwidth of a transmitting channel (txch), but smaller than the bandwidth of the transmitting band (tx).

Description

Antenna Device and Site Installation

for Mobile Radio Communication

The invention relates to a site installation for mobile radio communication and to an antenna device for a site installation.

A site installation for mobile radio communication is an instal- lation of devices at a location (site) which on the one hand convert the digital signals received from a digital interface to the switched network for mobile radio communication into suited radio frequency signals and send them in the form of radio frequency radiation to the mobile terminal devices in the surround- ings, and on the other hand receive signals in the form of radio frequency radiation from the mobile terminal devices in the surroundings and send them in a suited form to the interface to the switched network for mobile radio communication. A site installation for mobile radio communication generally consist of at least one base station and one or plural antennas. The functional units of a site installation may be arranged in different ways .

US 2001/0046225 Al describes a site installation the base sta- tion of which includes a transceiver. In the receiver path, the signals received from a receiver antenna are converted to an intermediate frequency and digitized. The digital tuner processes the entire bandwidth of the receiving band of the corresponding mobile radio communication standard such as GSM. The digital composite signal is divided by a digital channelizer into individual channels which are processed further by digital signal processors. In the transmitter path, the individual channels are combined by a digital combiner, and the combined signal is con- verted into a radio frequency signal in a broad band exciter. The radio frequency signal is amplified by a power amplifier and emitted by a transmitter antenna. A coder and a decoder form the interface to the switched network for mobile radio communica- tion. A CPU controlled by the switched network for mobile radio communication deals with the administration and setting of all the components.

US 2011/0310881 Al describes a site installation in which some of the components of the transmitter and receiver path are swapped out into a "Remote Radio Head" which is installed apart from the base station at the antenna mast. The digital data exchange between the base station and the remote radio head is carried out via a broad-band glass fiber cable.

WO 2012/027703 A2 describes a frontend for mobile phones in which the antennas, matching networks, filters and amplifiers used are formed tunable in their frequency. The object of the present invention is to provide a site installation for mobile radio communication and an antenna device for the site installation in which the antenna elements and filters required for the transmitter and receiver path are formed and arranged in a way from which considerable reductions of space requirements and costs result. The object of the present invention further is to provide a site installation for mobile radio communication and an antenna device for the site installation which is able to cover all the existing and planned mobile radio communication bands using few variants.

The object is attained by an antenna device according to claim 1, a site installation according to claim 9, and a use of an antenna device for a site installation according to claim 10. Fur- ther developments of the invention are indicated in the dependent claims, respectively.

The antenna device for a site installation for mobile radio com- munication includes at least one receiving path having at least one tunable receiver antenna element for receiving a mobile radio communication signal and at least one tunable receiver filter for filtering the signal from the least one tunable antenna element, wherein the receiver path has a bandwidth which is at least as great as the bandwidth of a receiving channel, but smaller than the bandwidth of the receiving band, and/or at least one transmitter path having at least one tunable transmitter filter for suppressing unwanted signals outside of the transmitting band and at least one tunable transmitter antenna element for emitting a mobile radio communication signal, wherein the transmitter path has a bandwidth which is at least as great as the bandwidth of a transmitting channel, but smaller than the bandwidth of the transmitting band. The tunable realization of the individual components of the transmitter or receiver path and the selection of a smaller bandwidth than the transmitting or receiving band lead to reduced requirements to the slope steepness and the quality factor of the filters used, so that the filter elements used may be re- alized considerably smaller and with lower costs. From this, considerable reductions of space requirements and costs result.

Further features and advantages of the invention will arise from the description of embodiments with reference to the enclosed figures. Fig. 1 shows a block diagram of a site installation for mobile radio communication according to an embodiment of the present invention. Fig. 2 schematically shows in four diagrams a) through d) the different requirements to filter units for a mobile radio communication band and a mobile radio communication channel . Fig. 3 shows existing or planned frequency bands for the mobile radio communication.

Fig. 4 shows a block diagram of a site installation for mobile radio communication according to a comparative example.

Fig. 5 shows an example of an arrangement of antenna elements.

Fig. 6 shows an example of a design of a tunable antenna element in a planar structure.

Fig. 7 shows a cross-section through the antenna element shown in Fig. 6.

Fig. 8 shows an example of a design of a tunable band pass.

Fig. 9 shows an example of a design of an adjustable phase

shifter .

Fig . 10 shows a block diagram of a site installation for mobile radio communication according to another embodiment of the present invention. In the following, an embodiment of the present invention is de scribed in detail with reference to the enclosed drawings.

Fig. 1 shows a block diagram of a site installation for mobile radio communication according to an embodiment of the present invention. The site installation includes a receiver 100, a transmitter 200, a control unit 300 and a basic unit 400.

On the one hand, the basic unit 400 is connected to the (not shown) switched network for mobile radio communication via the interface connector 401. On the other hand, it is connected to the receiver 100, the transmitter 200 and the control unit 300

The receiver 100 includes one or plural receiver stages. As an example, three receiver stages 101, 102, 103 are shown in Fig. 1. The receiver stages are connected to an associated receiver array 110, 120, 130, respectively. The receiver arrays 110, 120, 130 have the same configuration. As an example, the configuration of the receiver array 110 is described.

The receiver array 110 includes a receiver filter 111, one or plural receiver phase shifters 112 (or a receiver phase shifter having one or plural outputs) , and one or plural receiver antenna elements 113a, 113b, 113c. As an example, a receiver phase shifter having three outputs is associated to each receiver filter, and three receiver antenna elements are associated to each receiver phase shifter, respectively, in Fig. 1.

The receiver filter 111 and the receiver antenna elements 113a, 113b, 113c are tunable in an electronic or micromechanical way, i.e. their frequency position and/or matching can be varied. The receiver phase shifter 112 is adjustable in an electronic or mi- cromechanical way, i.e. the phase relation between its output signals can be varied.

The receiver filter 111 is connected on the one hand to the associated receiver stage 110, and on the other hand to the associated receiver phase shifter (s) 112. Each receiver phase shift er is connected to one or plural associated receiver antenna el ement(s) 113a, 113b, 113c. Each signal path consisting of a receiver filter, a receiver phase shifter and a receiver antenna element forms a receiver path in the corresponding receiver array .

The transmitter 200 includes one or plural transmitter stages. As an example, three transmitter stages 201, 202 and 203 are shown in Fig. 1. The transmitter stages are connected to an associated transmitter array 210, 220, 230, respectively. The transmitter arrays 210, 220, 230 have the same configuration. As an example, the configuration of the transmitter array 210 is described .

The transmitter array 210 includes a transmitter filter 211, one or plural transmitter phase shifters 212 (or a transmitter phase shifter having one or plural outputs) , and one or plural transmitter antenna elements 213a, 213b, 213c. As an example, a transmitter phase shifter having three outputs is associated to each transmitter filter, and three transmitter antenna elements are associated to each transmitter phase shifter, respectively, in Fig. 1. The transmitter filter 211 and the transmitter antenna elements 213a, 213b, 213c are tunable in an electronic or micromechanical way, i.e. their frequency position and/or matching can be varied. The transmitter phase shifter 212 is adjustable in an elec- tronic or micromechariical way, i.e. the phase relation between its output signals can be varied.

The transmitter filter 211 is connected on the one hand to the associated transmitter stage 210, and on the other hand to the associated transmitter phase shifter (s) 212. Each transmitter phase shifter is connected to one or plural associated transmitter antenna element (s) 213a, 213b, 213c. Each signal path consisting of a transmitter filter, a transmitter phase shifter and a transmitter antenna element forms a transmitter path in the corresponding transmitter array.

The control unit 300 is connected on the one hand to the basic unit 400, and on the other hand to the tunable receiver filters 111 etc., the adjustable receiver phase shifters 112 etc., the tunable receiver antenna elements 113a, 113b, 113c etc., the tunable transmitter filters 211 etc., the adjustable transmitter phase shifters 212 etc., and the tunable transmitter antenna elements 213a, 213b, 213c etc.

Examples of the configuration of the individual elements of the receiver or transmitter path are indicated below.

Fig. 6 shows an example of a configuration of a tunable antenna element which may be used as a receiver or transmitter antenna element. Fig. 7 shows a cross - section through the antenna element. The antenna element is formed in a planar technology. Such antennas are known under the name of patch antenna. On a substrate S having a substrate height (h) and a dielectric permit- tivity (e_r) , the rear face of which is entirely covered by a metal layer M, a rectangular conductive antenna area A is formed, having a length (1) and a width (w) . A variable capaci- tor CV which may for exampled be formed in an MEMS technology serves as a tuning element.

Fig. 8 shows an example of a configuration of a tunable band pass which may be used as a receiver or transmitter filter. In the indicated example, the tunable filter is formed as an LC filter composed of fixed and variable capacitors CF, CV and inductors L. Fig. 8 shows, as an example, a filter having two coupled resonators in which the center frequency may be made ad- justable by using variable capacitors CV.

Fig. 9 shows an example of a configuration of an adjustable phase shifter which may be used as a receiver or transmitter phase shifter. The phase shifter shown in Fig. 9 has an input El and two outputs Al, A2 for connecting two antenna elements. The input signal received via the input E is divided onto two paths in a power splitter T. In one of these paths, pieces of line LI, L2 having different lengths and switches S are arranged. These switches which are operable in an electronic or micro-mechanical way can set the signal path along the longer pieces of line LI or along the shorter pieces of line L2 and thus affect the phase at the output A2 with regard to the output Al .

During the operation, the basic unit 400 among others effects the conversion of the protocols of the air interface for the interface connector 401. On the one hand, all the signals from the receivers are detected and equalized in a way suited for the corresponding mobile radio communication standard or for plural mobile radio communication standards and processed according to the mobile radio communication standard. On the other hand, all the transmitter signals are generated in a digital form. The management and control of all the components of the site installation, especially the frequency tuning of the filters and an- tenna elements as well as the phase adjustment of the phase shifters is effected by the control unit 300.

In the receiving mode, the adjustable receiver antenna elements associated to a receiving path, for example the receiver antenna elements 113a, 113b, and 113c of the receiver array 110, receive a radio signal incoming as an electromagnetic radiation and output it in the form of an electrical radio frequency signal to the corresponding receiver phase shifter 112. By a small-band configuration of the receiver antenna elements as it can for example be achieved by the configuration as a planar antenna, filtering the received signal is achieved at the same time.

The adjustable receiver phase shifter 112 on the one hand ef- fects an adjustable directivity of the receiver antenna formed by the receiver antenna elements 113a, 113b, and 113c by adjusting the phases of the received signals of the receiver antenna elements 113a, 113b, and 113c. On the other hand, by equalizing the changed phase difference resulting from a change of the re- ceiving frequency, it makes sure that the relative phasing of the received signals and thus the directivity of the receiver antenna elements remains constant over a widely tunable frequency range. The receiver phase shifter 112 may effect a further filtering of the received signal.

The received radio frequency signal then arrives via the tunable receiver filter 111 in which it is further filtered and the receiver stage 103 in which it is converted to a digital signal at the basic unit 400 which processes it further in a known manner and transmits it via the interface connector 401 to the switched network for mobile radio communication. Filtering the received signal is thus achieved in plural stages by the small-band receiver antenna elements 113a, 113b, and 113c, the receiver phase shifter 112 and the receiver filter 111. In the process, the receiver filter 111 only has to achieve the remaining filter effect required which could not yet be achieved by the receiver phase shifter 112 and the receiver antenna elements 113a, 113b, and 113c.

In the transmitting mode, the basic unit 401 processes a signal received via the interface connector 401 from the switched network for mobile radio communication and outputs it as a digital signal to the corresponding transmitter stage, for example the transmitter stage 201, in which it is converted to a radio frequency transmit signal and amplified to the desired level. In the reverse order as in the receiving path, the transmit signal is then transmitted via the tunable transmitter filter 211 and the adjustable transmitter phase shifter 212 to the tunable transmitter antenna elements 213a, 213b, 213c associated to the corresponding transmitting path which emit the signal as an electromagnetic radio signal. By a small-band configuration of the transmitter antenna elements as it can be achieved for example by the configuration as planar antenna, filtering the transmit signal is achieved at the same time. The adjustable transmitter phase shifter 212 on the one hand effects an adjustable directivity of the transmitter antenna formed by the transmitter antenna elements 213a, 213b, and 213c by adjusting the phases of the transmit signals of the transmitter antenna elements 213a, 213b, and 213c. On the other hand, by equalizing the changed phase difference resulting from a change of the receiving frequency, it makes sure that the relative phasing of the transmit signals and thus the directivity of the transmitter antenna elements remains constant over a widely tun- able frequency range. The transmitter phase shifter 212 may effect a further filtering of the transmit signal.

In the same way as filtering the received signal, filtering the transmit signal is thus achieved in plural stages, too, by the small-band transmitter antenna elements 213a, 213b, and 213c, the transmitter phase shifter 212 and the transmitter filter 211. In the process, the transmitter filter 211 only has to achieve the remaining filter effect required which could not yet be achieved by the transmitter phase shifter 212 and the transmitter antenna elements 213a, 213b, and 213c.

The required setting of all the tunable elements to the desired frequency range (the receive or transmit frequency of the corre sponding receiving or transmitting channel) is effected by the control unit 300.

In Fig. 2, some diagrams are indicated versus the frequency, showing the frequency curves in mobile radio communication for the FDD mode (frequency division duplexing) .

Diagram a) shows a distribution of bands for the case that the receiving band rx is located below the transmitting band tx. The bands rx and tx are separated by the duplex gap (g) .

In Diagram b) , a single receiving channel rxch and a single transmitting channel txch are shown by way of example, each being located in the receiving band rx or the transmitting band tx, respectively. The receiving channel and the transmitting channel txch are spaced by a frequency distance (dx) from each other which is called duplex spacing. Diagram c) schematically shows the requirement to a receiver filter which is suited for the corresponding mobile radio communication band. The necessary stop-band attenuation is therein designated by as.

Diagram d) shows as an example the filtering requirement to a receiver filter which is optimized for the receiving channel rxch. The necessary stop-band attenuation is therein also designated by as .

Fig. 3 shows various existing or planned frequency bands for the mobile radio communication. As can be conceived from the figure, these frequency bands differ from each other by their position within the frequency range, the bandwidth of their lower and up- per band which are used as a receiving band or transmitting band, respectively, and the duplex gap between the receiving band and the transmitting band. Altogether, these mobile radio communication bands are located within a frequency range between 500 and 4000 MHz.

According to the present invention, each transmitter path has a bandwidth (= a difference between the two frequencies at which the attenuation is 3dB) which is at least as great as the bandwidth of a transmitting channel txch, but smaller than the band- width of the transmitting band tx. In a similar way, each receiver path has a bandwidth which is at least as great as the bandwidth of a receiving channel rxch, but smaller than the bandwidth of the receiving band rx. Each transmitter or receiver path thus may serve to the transmission of a single transmitting or receiving channel or to the transmission of adjacent channels, but not to the transmission of the entire transmitting or receiving band. The adjustable filters achieve the rest of the necessary filter effect which cannot achieved by the combined filter effects of the adjustable phase shifter and the tunable antenna element. In order not to affect the receiver sensitivity, signals which the transmitter generates outside of the transmitting band tx, especially those which it generates within the receiving band rx, have to be suppressed. On the one hand, this is achieved by the filter effect of the tunable transmitter filters, the ad- justable transmitter phase shifters and the tunable transmitter antenna elements, but on the other hand also by an isolation of transmitter and receiver antennas. Such an isolation is for example achieved by using planar technologies because planar antennas have a lower mutual coupling in comparison to common di- poles, and by a special arrangement of transmitter and receiver antenna elements .

Fig. 5 shows an example of an arrangement of transmitter and receiver antenna elements. On a substrate S, all the transmitter antenna elements are arranged in the region designated by tx, and all the receiver antenna elements are arranged in the region designated by r . The distance and the polarization of the corresponding antenna elements are essential for the isolation. In the arrangement shown in Fig. 5, antenna elements next to each other either have a large distance a or a different polarization. In the example shown in Fig. 5, all odd-numbered antenna elements are polarized horizontally (h) , and all even-numbered antenna elements are polarized vertically (v) . For illustrating the effects of the invention, Fig. 4 shows a site installation for mobile radio communication according to a comparative example. The same or similar elements as those shown in Fig. 1 are designated by the same reference signs, and their description is not repeated.

The site installation according to the comparative example in- eludes a base station 500 and an active antenna 600 which are connected to each other by an interface cable 510. Generally, the base station is accommodated in a building, whereas the antenna is mounted on a rooftop or at an antenna mast. Like in the present embodiment, the base station 500 includes a basic unit 400 which is connected to the (not shown) switched network for mobile radio communication via the interface connector 401. The base station 500 further includes a digital interface unit 501 which is connected on the one hand to the basic unit 400, and on the other hand to the interface cable 510 by which the digital transmit and receive signals are transmitted fro and back between the base station 500 and the active antenna 600 in a multiplex mode. Correspondingly, the active antenna 600 also includes a digital interface unit 601 for the communication with the base station 500 via the interface cable 510 in a multiplex mode. In a similar way as in the present embodiment, the active antenna 600 further includes receiver and transmitter stages 602, 603, re- ceiver and transmitter filters 611, 612, receiver and transmitter phase shifters 620, 630 as well as receiver and transmitter antenna elements 621a-c, 631a-c. These elements, however, differ from those of the present embodiment in that they are not tunable. Further, they have a broad-band configuration so that each individual receiver and transmitter path covers the full frequency range of the receiving or transmitting band. The phase shifters 620 and 630 are adjusted by a mechanical apparatus 641 which is driven by a motor 640. The radio frequency signals received in the broad-band receiver antenna elements 621a_; 621b, 621c are added in the mechanically adjustable phase shifter 620 and transferred to the non-tunable broad-band receiver filter 611 which filters out all the signals of a specific receiving band. From there, the signals are led further to the receiver stages 613 in which they are converted into digital signals. The transmit signals of mobile radio communication band are converted into a radio frequency transmit signal in the transmitter stages 603 and are filtered in common in the non-tunable broadband transmitter filter 612. Via the mechanically adjustable phase shifter 620, the filtered signal is distributed to the broad-band transmitter antenna elements 631a, 631b, 631c from which they are emitted.

In such a site installation, three-dimensional dipole structures are generally used as broadband transmitter and receiver antenna elements.

As can be seen from Fig. 2, the requirements to the selectivity of the filters used are, for the same stop-band attenuation (as) , less severe in the case in which the filter band width corresponds to the bandwidth of a receiving or transmitting channel rxch, txch than in the case in which the filter band width corresponds to the bandwidth of a receiving or transmitting band rx, tx. For example, the slope Fl of the receiver filter shown in diagram c) of Fig. 2 in the case in which the re- ceiver filter bandwidth corresponds to the bandwidth of the receiving band rx has to achieve the desired stop-band attenuation (as) over the in general relatively small frequency distance of the duplex gap (g) . The slope F2 of the receiver filter shown in diagram d) of Fig. 2 in the case in which the receiver filter bandwidth corresponds to the bandwidth of the receiving channel rxch, however, can be considerably more gentle because it has to achieve the desired stop-band attenuation (as) over the consid- erably larger duplex spacing (dx) .

For a realization of the transmitter and receiver filter, this means that the requirements to the filters are considerably reduced. If the filter bandwidth has to cover the entire receiving or transmitting band, not only the required order of the filters has to be high, but also the required quality factor of the filters. In practice, high-quality resonator filters are therefore used for this case which usually have to be formed by silver- coated aluminum. According to the present invention, however, considerably less expensive and smaller filters may be used.

By separating the receiver and transmitter antenna elements, and by an arrangement which is also optimized for the isolation of the antenna elements, as it has been described with reference to Fig. 5, together with a planar configuration of the antenna elements, an improved isolation can be achieved by the present invention .

In comparison to the broad-band three-dimensional dipole struc- tures which are usual in the mobile radio communication, planar antenna structures have a small-band characteristic. While conventional dipoles have a relative bandwidth (ratio of the 3dB bandwidth to the center frequency) of more than 10%, the relative bandwidth of the small -band planar antennas is less than 5%, typically less than 3%. By the tunability and the reduction of the required bandwidth as far as a channel bandwidth, planar antennas may be used in the present invention. Thus, considera- ble advantages relating to the required space and the manufacturing costs of such an equipment may result.

Since the receiver and transmitter antennas as well as the re- ceiver and transmitter filters have a smaller bandwidth in comparison to the prior art, better operation parameters such as insertion loss, antenna efficiency and the like can be achieved.

The electronic or micro-mechanical adjustability of the phase shifters result in that, on the one hand, the relative phase position of the transmitter and receiver dipoles and thus the emitting characteristic in the entire adjusting range can be held constant. On the other hand, the emitting characteristics of the transmitter and receiver dipoles can be performed by an electronic device having a small space requirement.

A further advantage of the present invention is that the site installation according to the comparative example which has been described on the basis of Fig. 4 is designed in a band specific way. This means that for each of the mobile radio communication bands shown in Fig. 3, a site installation of its own has to be provided .

The site installation according to the present embodiment, how- ever, can be tunable across plural mobile radio communication bands so that it is no longer required to provide a specific site installation for each frequency band. If a tuning range (ratio of the highest achievable center frequency to the lowest achievable center frequency) of 2:1 is taken as a basis for the tunable site installation described in Fig. 1, for example only three differently dimensioned transmitter and receiver paths are required for covering all the mobile radio communication bands shown in Fig. 3. Such a tuning range can easily be achieved by a configuration of the individual components as described above. For the manufacturers, this results in considerable reductions of development efforts, logistics and costs. Another embodiment of the present invention is shown in Fig. 10. The same or similar elements as those shown in Fig. 1 and 4 are designated by the same reference signs, and their description is not repeated. In contrast to the embodiment shown in Fig. 1 which may be integrated as a whole within a casing and mounted on an antenna mast, the site installation of the present embodiment is divided into a base station 500 and an active antenna 610 which are connected to each other via an interface cable 510, similar as in the comparative example shown in Fig. 4.

The base station 500 is constructed like in the comparative example. The active antenna 610 includes all the elements of the site installation shown in Fig. 1 except the basic unit 400 which according to the present embodiment is included in the basic station 500. Instead, the active antenna 610 includes, like in the comparative example, a digital interface unit 601 for the communication to the base station 500 via the interface cable 510 in a multiplex mode. Also in the present embodiment, the base station is preferably accommodated in a building, whereas the active antenna is mounted on a rooftop or at an antenna mast.

The operation of the site installation according to the present embodiment corresponds to the operation of the site installation according to the embodiment shown in Fig. 1. Thus, the same effects and advantages can be achieved. In the site installation according to the present embodiment, possibly required modifica- tions for an adaptation to changed standards which only relate to the digital signal processing can be performed in an easier way because the digital signal processing is carried out in the basic unit 400 which according to the present embodiment is in- eluded in the base station 500 and can be accessed in an easier way due to its position within a building.

Even if the above embodiments have been described for a site installation having three receiver and transmitter paths, the num- ber of possible channels is not restricted to this example, and the site installation may have more or less than three receiver and transmitter paths, and the number of receiver and transmitter paths may differ from each other. The site installation may also include one or plural receiver paths and no transmitter path, or one or plural transmitter paths and no receiver path.

In all the embodiments described above, the number of receiver and transmitter stages, the number of tunable filter for each receiver or transmitter stage, the number of adjustable phase shifters (or of the phase shifter outputs) for each filter and the number of der antenna elements for each phase shifter are not delimited to the examples indicated in the figures, but may be freely selected depending on the desired application.

Claims

1. An antenna device for a site installation for mobile radio communication, including:

at least one receiving path, including:

at least one tunable receiver antenna element (113a- 113c) for receiving a mobile radio communication signal, and

at least one tunable receiver filter (111) for filter- ing the signal from the least one tunable antenna element,

wherein the receiver path has a bandwidth which is at least as great as the bandwidth of a receiving channel (rxch) , but smaller than the bandwidth of the receiving band (rx) ,

and/or at least one transmitter path, including:

at least one tunable transmitter filter (211) for suppressing unwanted signals outside of the transmitting band, and at least one tunable transmitter antenna element

(213a-213c) for emitting a mobile radio communication signal, wherein the transmitter path has a bandwidth which is at least as great as the bandwidth of a transmitting channel

(txch) , but smaller than the bandwidth of the transmitting band (tx) .

2. The antenna device according to claim 1, including:

more than one tunable receiver antenna element (113a-113c) and at least one adjustable receiver phase shifter (112) for adjusting the phases of the signals received by the receiver antenna elements, and/or

more than one tunable transmitter antenna element (213a- 213c) and at least one adjustable transmitter phase shifter

(212) for adjusting the phases of the signals supplied to the transmitter antenna elements.

3. The antenna device according to claim 1 or 2 , wherein the receiver filter (111) and/or the receiver phase shifter (112) and/or the receiver antenna element (s) (113a, 113b, 113c) and/or the transmitter filter (211) and/or the transmitter phase shift- er (212) and/or the transmitter antenna element (s) (213a, 213b, 213c) are tunable or adjustable in an electronic or micro- mechanical way.

4. The antenna device according to one of the claims 1 through 3, wherein the tuning range of the receiver path and/or the transmitter path is greater than a mobile radio communication band and preferably includes plural mobile radio communication bands .

5. The antenna device according to one of the claims 1 through

4, wherein the receiver antenna element (s) (113a, 113b, 113c) and/or the transmitter antenna element (s) (213a, 213b, 213c) have a small-band configuration.

6. The antenna device according to one of the claims 1 through

5, wherein the receiver antenna element (s) (113a, 113b, 113c) and/or the transmitter antenna element (s) (213a, 213b, 213c) are formed as planar antenna elements .

7. The antenna device according to one of the claims 1 through 5, wherein the receiver antenna element (s) (113a, 113b, 113c) and/or the transmitter antenna element (s) (213a, 213b, 213c) are tunable by means of variable capacitors which are formed in MEMS technology .

8. The antenna device according to one of the claims 1 through 7, further including a control unit (300) for controlling all the tunable elements .

9. A site installation for mobile radio communication, including

an antenna device according to one of the claims 1 through 8 , and

a basic unit (400) for digital signal processing and for communication with the switched network for mobile radio communication .

10. Use of an antenna device according to one of the claims 1 through 8 for a site installation for mobile radio communication .