GB2279504A - Antenna system - Google Patents
Antenna system Download PDFInfo
- Publication number
- GB2279504A GB2279504A GB9312729A GB9312729A GB2279504A GB 2279504 A GB2279504 A GB 2279504A GB 9312729 A GB9312729 A GB 9312729A GB 9312729 A GB9312729 A GB 9312729A GB 2279504 A GB2279504 A GB 2279504A
- Authority
- GB
- United Kingdom
- Prior art keywords
- units
- series
- fed
- combining
- radio frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/30—Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
Landscapes
- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
In a method of combining a series of radio frequency signals having different frequencies, the signals are fed to the respective inputs of a first set of hybrid power combiner units 31, 32 and the outputs from this first set of units are optionally fed to further sets of such units 33, 34. The signal outputs of the final set of units are fed to the radiating elements 35 - 38 of an antenna array. In a modification, a pair of signals is fed to a single hybrid power combiner unit and each output of the unit is fed to a separate antenna. Hybrid combiner units may be branch line couplers formed from a combination of series and shunt transmission line sections in microstrip form or they could be hybrid ring couplers. The radiating elements in the antenna array are preferably arranged to provide a uniform output signal in the azimuth plane by stacking or spacing around a structure in opposite azimuth directions. In a most preferred embodiment the antennas in the array are used for both transmission and reception and are fitted with a duplexor so that transmitted and received signals do not interact. <IMAGE>
Description
ANTENNA SYSTEM
This invention relates to an antenna system adapted to accept multi-channel signal sources in both in transmission and reception modes.
In modern communication networks. particularly those associated with cellular communication systems there is a need to combine a the power outputs of a number of radio transmitters having different carrier frequencies and transmit them from a single antenna system; a so-called
channelized scheme . It is essential that the outputs of the transmitters are combined in a manner that is linear so that no intermodulation takes place. Currently two devices are used for achieving this object. a hybrid power combiner unit or a cavity filter power combiner unit.
A hybrid power combiner unit comprises two input and two output ports all having the same impedance. If two signals are supplied to such a unit. one to each input port. then at each output port there will be a signal which is equal to the sum of both input signals at half power.
As the purpose of such a unit is to provide a combined signal source only one output is used and the other is terminated in a matched load. The overall loss when combining two signals in such a unit will inevitably be 3 dB and in practice further losses will occur due to power losses in the circuitry.
If more that two input signals are combined by means of a plurality of hybrid power combiner units the losses will be considerably greater. For example to combine four separate input signals it is necessary to use three hybrid power combiner units. Pairs of signals are supplied to two separate units and one of the outputs of each of these units is combined in a third unit. The combination of four signals taken from this unit will have suffered a loss of at least 6 dB. As the number of transmitter outputs and associated hybrid combiner units increases the signal losses escalate.
A cavity filter power combiner unit provides a lower loss means of combining signals than hybrid power combiner units. A cavity filter unit comprises a bank of highly selective tuned bandpass filters. one per input signal.
Each filter is tuned to the frequency of its associated input signal so as to isolate the signal source from the other signal sources when the filter outputs are combined.
The loss between each signal source and the combined output will be about 4 to 6 dB caused by the filter insertion loss in the associated highly selective filter.
It will be seen that the use of cavity filter power combiner units provides a lower loss but at the cost of increased complexity and the use of complex and expensive filters. The signals combined must also be restricted to a fixed frequency. i.e. not allowed to frequency hop. since the speed at which the cavity filter can retune is generally slow.
According to the present invention there is provided a method of combining a series of radio frequency signals having different frequencies using hybrid power combiner units. characterised in that a series of said signals are fed to the respective inputs of a first set of hybrid power combiner units. the outputs from the first set of units are optionally fed to further sets of said units and the signal outputs of the final set of units are fed to the radiating elements of an antenna array.
In a most preferred embodiment the radiating elements in the antenna array are arranged to provide a substantially uniform output signal in the azimuth plane.
In the case of a pair of signals fed to a single hybrid power combiner unit each output is fed to a separate antenna. In order to achieve omni-directional radiation the antennas may be stacked or spaced appropriately around a structure in opposite azimuth directions. The power dissipated in the matched loads associated with prior systems using hybrid power combiner units is usefully radiated in the method of the invention.
The method can be extended to a large number of signals by forming a matrix using hybrid converter units. The number of radiating antenna units will equal the number of signals entering the matrix. The individual antennas may be combined to form an omnidirectional transmitting array in known manner. The antennas used in the array may also be used for reception. Each antenna is fitted with a duplexor allowing it to accept a signal from a transmitter source and to pass a signal to a receiver without interaction. The received signal is fed to a low noise preamplifier. which is preferably fitted close to the antenna. and then onwards to a receiver. Each antenna may be fed to a single receiver or the received signals from the low noise amplifiers may be combined. optionally amplified. and fed to separate receivers to ensure omnidirectional reception.
In order that the invention may be clearly understood it will now be described with reference to the accompanying drawings in which:
Figure 1 shows the method of combining four signals using a hybrid power combiner unit according to the prior art.
Figure 2 shows the method of combining two signals using a hybrid combiner unit according to the invention
Figure 3 shows the method of combining four signals using hybrid combiner units according to the invention
Figure 4 shows the method of combining eight signals using hybrid combiner units according to the invention. and
Figure 5 shows a complete station transmission and reception system using the method of combining signals according to the invention
A signal combination system. see Figure 1 . consists of three hybrid power combiner units 1. 2 and 3. The hybrid power combiner units may be a branch line coupler formed from a combination of series and shunt transmission line sections in microstrip form or a hybid-ring coupler. Each power combiner unit has a pair of input ports. 4 to 9. and a pair of output ports. 10 to 15.
The outputs of two separate transmitters. Tx1 and Tx2.
having different carrier frequencies are fed respectively to the input ports 4 and 5 of unit 1. Similarly the outputs of two further transmitters. Tx3 and Tx4. also having different carrier frequencies. are fed to the input ports 6 and 7 of unit 2. The power outputs from the output port 10 of unit 1 and 12 of unit 2 are fed respectively to the input ports 8 and 9 of unit 3. The outputs of the ports 11. 13 and 15 of each of the units 1. 2 and 3 are terminated in matched loads 16. 17 and 18 which dissipate the power output from these ports It will thus be seen that half the power of the combined transmitter outputs Tx1 and Tx2 is dissipated in load 16. half the power of the combined transmitter outputs Tx3 and Tx4 is dissipated in load 17 and half the power of the combination of the outputs Tx1 Tx2. Tx3 and Tx4 is dissipated in load 18 giving a total power loss of 6 dB. In practice the circuit losses in the units 1. 2 and 3 will bring the total amount of transmitter power loss to a greater value.
In the method of combining two signals according to the invention. see Figure 2. the transmitter power outputs Tx1 and Tx2 are fed to input ports 21 and 22 of a hybrid power combiner unit 23. One output port 24 supplies a signal representing a combination of outputs Tx1 and Tx2 at approximately half the power of each of the inputs.
Similarly output port 25 supplies the same half power combination of outputs The output power from each of the ports 24 and 25 is each fed directly or through matching means. not shown. to separate antennas. not shown. The antenna directional radiation patterns are arranged in known manner to provide a substantially uniform radiation pattern in the azimuth plane.
The method of combining the power outputs of four transmitters using hybrid power combiner units according to the invention see Figure 3. uses four hybrid combiner units 31. 32. 33 and 34 connected in the form of a matrix. The four transmitter outputs Tx1 Tx2. Tx3 and Tx4 are fed respectively to the four input ports of the first pair of combiner units 31 and 32. The outputs of these units are fed with appropriate cross connections to the second pair of units 33 and 34. The output ports of the second pair of units will provide four outputs each representing a combination of transmitter outputs Tx1. Tx2. Tx3 and Tx4 and each at a power level one quarter of that of the input power level. Each power output from the matrix is fed directly or through matching means. not shown. to separate antennas 35. 36. 37 and 38. The antennas are arranged to form part of an array providing a substantially uniform radiation pattern in the azimuth plane. Apart from the circuit losses in the hybrid combiner units 31. 32. 33 and 34 all the power from the transmitters Tx1 Tx2. Tx3 and
Tx4 is usefully radiated.
An extension of the method of combining four transmitter outputs using hybrid power combiner units connected in a matrix. see Figure 4. uses twelve identical hybrid combiner units 40 in three rows. A. B and C. Eight signals. Tx1 to
Tx8 are fed to the input ports of the combiner units 40 forming row A. the input row. The output ports of the units in row A are fed with appropriate cross connections to the units 40 forming row B. the intermediate row. In turn the output ports of the units in row B are fed with appropriate cross connections to the units forming row C.
the final row. The eight output ports from the units of row C each represent a combination of the eight inputs at an eighth of the input power. The eight output signals are fed to separate directional antennas 41 as described previously so that the array provides a substantially uniform radiation pattern in the azimuth plane. In the interconnections between the units 40 phase changing elements may be included in known manner.
A complete station for transmission and reception of signals. see Figure 5. has a four input matrix combiner 50 of the type described with reference to Figure 3 adapted to accept four transmitter outputs. The outputs of the combiner 50 are fed through duplexor units 51 to an array of antennas 52. The antennas 52 are arranged as described previously so that the array provides a substantially uniform radiation pattern in the azimuth plane. The receiver outputs from the duplexors 51 are fed to a set of low noise preamplifiers 53 located close to the duplexor units on the antenna array. The outputs from the amplifiers 53 are fed through suitable low loss cable to receiver units. not shown. The antenna array will usually share its elevated site with other antennas which may be associated with the same communication network or independent. Such antennas 54 are shown together with duplexor units 55 and low noise amplifiers 56.
The method of method of combining a series of radio frequency signals having different frequencies using hybrid power combiner units described herein may be used over a wide range of frequencies from 100 MHz to 4 GHz. The circuit elements and their arrangement in the construction of the hybrid power converter will depend upon the centre band of frequencies being combined and the overall banwidth to be accomodated. The method is of particular value in the range 700 MHz to 2 GHz using a bandwidth of 10Mhz or greater enabling a combination of the outputs of 32 transmitters to be achieved. The signal power outputs of the transmitters involved may lie in the range from 0.1 to 200 watts.
Claims (13)
1. A method of combining a series of radio frequency signals having different frequencies using hybrid power combiner units. characterised in that a series of said signals are fed to the respective inputs of a first set of hybrid power combiner units. the outputs from the first set of units are optionally fed to further sets of said units and the signal outputs of the final set of units are fed to the radiating elements of an antenna array.
2. The method of combining a series of radio frequency signals as claimed in claim 1. characterised in that a pair of signals is fed to a single hybrid power combiner unit and each output is fed to a separate antenna.
3. The method of combining a series of radio frequency signals as claimed in claim 1. characterised in that a plurality of signals is fed to a matrix of hybrid converter units and the final set of units are fed to a plurality of radiating antenna units which equals the number of signals entering the matrix.
4. The method of combining a series of radio frequency signals as claimed in any of the preceding claims.
characterised in that the hybrid power combiner units are branch line couplers formed from a combination of series and shunt transmission line sections in microstrip form.
5. The method of combining a series of radio frequency signals as claimed in any of the claims 1 to 3.
characterised in that the hybrid power combiner units are hybid-ring couplers.
6. The method of combining a series of radio frequency signals as claimed in any of the preceding claims.
characterised in that the radiating elements in the antenna array are arranged to provide a substantially uniform output signal in the azimuth plane.
7. The method of combining a series of radio frequency signals as claimed in claim 6. characterised in that in order to achieve omni-directional radiation the antennas are stacked or spaced appropriately around a structure in opposite azimuth directions.
8. The method of combining a series of radio frequency signals as claimed in either claim 6 or claim 7. characterised in that the antennas used in the array are also be used for reception.
9. The method of combining a series of radio frequency signals as claimed in claim 8. characterised in that each antenna is fitted with a duplexor allowing it to accept a signal from a transmitter source and to pass a signal to a receiver without interaction.
10. The method of combining a series of radio frequency signals as claimed in either claim 8 or claim 9. characterised in that the received signal is fed to a low noise preamplifier fitted close to the antenna and then onwards to a receiver.
11. The method of combining a series of radio frequency signals as claimed in claim 10. characterised in that the amplified received signals from each antenna are combined.
optionally amplified. and fed to separate receivers to ensure omnidirectional reception.
12 Methods of combining a series of radio frequency signals as claimed in claim 1 and as herein described.
13. Methods of combining a series of radio frequency signals as herein described. and as shown in. the accompanying drawings.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9312729A GB2279504A (en) | 1993-06-19 | 1993-06-19 | Antenna system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9312729A GB2279504A (en) | 1993-06-19 | 1993-06-19 | Antenna system |
Publications (2)
Publication Number | Publication Date |
---|---|
GB9312729D0 GB9312729D0 (en) | 1993-08-04 |
GB2279504A true GB2279504A (en) | 1995-01-04 |
Family
ID=10737487
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9312729A Withdrawn GB2279504A (en) | 1993-06-19 | 1993-06-19 | Antenna system |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2279504A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2304496A (en) * | 1995-08-17 | 1997-03-19 | Motorola Ltd | Coupling radio transmitters to antenna elements |
WO1998043315A1 (en) * | 1997-03-24 | 1998-10-01 | Telefonaktiebolaget Lm Ericsson (Publ) | Integrated transmit/receive antenna with arbitrary utilisation of the antenna aperture |
US5854986A (en) * | 1995-05-19 | 1998-12-29 | Northern Telecom Limited | Cellular communication system having device coupling distribution of antennas to plurality of transceivers |
EP1253723A1 (en) * | 2001-04-23 | 2002-10-30 | Lucent Technologies Inc. | Transmitter/receiver device with re-configurable output combining |
EP1680860A2 (en) * | 2003-10-29 | 2006-07-19 | University Of Pittsburgh Of The Commonwealth System Of Higher Education | Energy harvesting circuit |
WO2012034804A1 (en) * | 2010-09-17 | 2012-03-22 | Rohde & Schwarz Gmbh & Co. Kg | High-frequency signal combiner |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1555591A (en) * | 1976-09-01 | 1979-11-14 | Tekade Felten & Guilleaume | Circuit arrangement for the mutually decoupled connection of a plurality of transmitters with different transmission frequencies to an aerial system |
GB2182206A (en) * | 1985-10-23 | 1987-05-07 | British Broadcasting Corp | Adaptable transmitter and antenna arrangement |
GB2209629A (en) * | 1987-09-09 | 1989-05-17 | Era Patents Ltd | Networks for antenna arrays |
-
1993
- 1993-06-19 GB GB9312729A patent/GB2279504A/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1555591A (en) * | 1976-09-01 | 1979-11-14 | Tekade Felten & Guilleaume | Circuit arrangement for the mutually decoupled connection of a plurality of transmitters with different transmission frequencies to an aerial system |
GB2182206A (en) * | 1985-10-23 | 1987-05-07 | British Broadcasting Corp | Adaptable transmitter and antenna arrangement |
GB2209629A (en) * | 1987-09-09 | 1989-05-17 | Era Patents Ltd | Networks for antenna arrays |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5854986A (en) * | 1995-05-19 | 1998-12-29 | Northern Telecom Limited | Cellular communication system having device coupling distribution of antennas to plurality of transceivers |
GB2304496A (en) * | 1995-08-17 | 1997-03-19 | Motorola Ltd | Coupling radio transmitters to antenna elements |
WO1998043315A1 (en) * | 1997-03-24 | 1998-10-01 | Telefonaktiebolaget Lm Ericsson (Publ) | Integrated transmit/receive antenna with arbitrary utilisation of the antenna aperture |
US6043790A (en) * | 1997-03-24 | 2000-03-28 | Telefonaktiebolaget Lm Ericsson | Integrated transmit/receive antenna with arbitrary utilization of the antenna aperture |
JP2001518265A (en) * | 1997-03-24 | 2001-10-09 | テレフオンアクチーボラゲツト エル エム エリクソン(パブル) | Integrated transmit / receive antenna with optional antenna aperture |
EP1764867A1 (en) * | 1997-03-24 | 2007-03-21 | Telefonaktiebolaget LM Ericsson (publ) | Integrated transmit/receive antenna with arbitrary utilisation of the antenna aperture and plural transmit subarrays |
EP1253723A1 (en) * | 2001-04-23 | 2002-10-30 | Lucent Technologies Inc. | Transmitter/receiver device with re-configurable output combining |
EP1680860A2 (en) * | 2003-10-29 | 2006-07-19 | University Of Pittsburgh Of The Commonwealth System Of Higher Education | Energy harvesting circuit |
EP1680860A4 (en) * | 2003-10-29 | 2008-11-19 | Univ Pittsburgh | Energy harvesting circuit |
WO2012034804A1 (en) * | 2010-09-17 | 2012-03-22 | Rohde & Schwarz Gmbh & Co. Kg | High-frequency signal combiner |
US9231288B2 (en) | 2010-09-17 | 2016-01-05 | Rohde & Schwarz Gmbh & Co. Kg | High frequency signal combiner |
Also Published As
Publication number | Publication date |
---|---|
GB9312729D0 (en) | 1993-08-04 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |