GB2538070A - Antenna system - Google Patents

Abstract

An antenna array system 10 or a method of operating such a system, comprises: a plurality of dipole radiating elements 30 in a first vertical column 12 with first and second antenna sub-arrays 33-1, 33-2,...33-8 with respective ports 13-1, 13-2 and polarisations P1, P2 and a plurality of dipole radiating elements in a second vertical column 14 with third and fourth antenna sub-arrays 34-1, 34-2,...34-8 with respective ports 13-3, 13-4 and polarisations P3, P4 and at least a first radio 40 including a first channel 51 with a transmission sub-channel 51T and a receiving sub-channel 51R and where each of the sub-channels 51T, 51R are connected to the opposite of a first vertical column antenna sub-array port or a second vertical column antenna sub-array port and likewise for a second channel 52; and each antenna sub-array includes an antenna element feed network 91, 92, 93, 94 for individually adjusting the tilt angle of a beam associated with an antenna sub-array. The system may include duplex filters for respective antenna array columns 12, 14 or ports 13-1, 13-2, 13-3, 13-4 which may be provided within the radio 40. The system may include a second radio which operates at a different frequency range to that of the first radio 40 and may be operated by a different network operator. Phase shifters may be used to provide different tilt angles to the antenna sub-arrays.

Description

Ante ia system [00011 None

Field of e Invention

[0002J The disclosure relates to m active antenna array s Tett:lino/onMal / [0003] An antenna array comprises a plurality of antenna elements. The antenna elements are typically radiating elements or groups of radiating elements, One example of an antenna array is an arrangement of sots: of radiating elements or radiating: element groups with individual ones of the radiating elements arranged: vertically on top of each other and arranged horizon, tally in a side,by,side-matmer, so that a two-dimensional array layout results. One example of such a twodimensio.nal antenna array has tbur vertical columns and arranged horizontally next to one another. Each of the vertical: columns contains, for example; six to ten radiating ts or radiating clement groups that are offset one above the other. These antenna arrays te used it mobile telephone communications, for example in the fiNtioney ranges 800 MHz o1.000 MHz and 1700 Wiz: to 2700 MHz, [0004] The antenna Oen either single polarized or dual The use of dual polarized antenna elements enables the antenna array to also send and tr Motions signal with a polarization: alignment of -/-45[deg.1 or 45[deg,1 horizontal direction or the vertical direction.

[00051ftc antenna arrays can receive teleecnnmunicatmns signal fro number of throe-ansmit a telecommuwith respect to the titans. At the same time, it is also possible to alter the beam direction of transmitted telecommunications signals from the antenna array by suitable adjustment of the phase angle and/or :amplitude of the telecommunicationsligtiah fed into the individual antenna elements, i.e. is possible to achieve a sclectne beam shaping of he ransmitted telecom [0006] The u known in the if phase:shifters in feeding networks for altering the beam direction is also shaping network may comprise, for example, a Bader matrix, has four inputs and four outputs. The beam-shaping network generates a different, but fixed phase relationship between the radiating elements in the antenna array according to the input selected. Such an antenna construction using a Butler matrix is known in the art in U.S, Pat. No. 6,351,243.

[0007] Electric tilting of horizontal field pattern can also he undertaken through the phase shifters between the columns. The use of phase shifters also allows the vertical radiatedE field pattern to be raised or lowered (down-tilting) [0008] The columns of the antenna y can be operated such that the individual columns are operated independently. This enables he different columns to be operated independently of each other, Ihr example in a transmit node or a receive mode. Furthermore, the different columns can be used for MIMO-operation by providing spatially separated MIMO-channels or for Multi-operator purposes, i.e. different mobile communication operators can share one antenna array by using different columns.

[0009] The individual radiating elements or radiating element groups are arranged produce an antenna array with radiated field pattern, whose half power beam width (HI of the main lobe in the horizontal direction is between te roughly 501.1degl and 00(deg.l, Especially in standard multicolumn configurations. only re beam widths are possible (80° to 100°) because of the physical enironment ot the radiators roam] use oases for the antenna arrays areas are known, in which the horizontal half power width of a muiticolumn antenna array needs to be in the order of 601deg.1 to 65[dEeg.] 30 per column, Attempts have already been made to arrange the radiating elements or radiating element groups in the individual columns at different horizontal positions in the same (logical) columns. This arrangement affects the half power beam width of the horizontal beam: pattern of the respective column of the antenna array. ,Horizontal half power beam widths of between 60/deg,/ and 701derid can be achieved by this arrangement.

[00111 The commonly owned patent publication ITS 6,94' (Gott1, RumoId) discloses an example of the antenna array having at least two vertical columns, in which the horizontal half power beam width one individual column is lowered even to values between 60jdegl and 70[degl, US '732 also teaches an antenna array with two columns arranged vertically and having two groups of radiating elements arranged together in a vertical direction. In at least one of the columns, two or more of the radiating elements are arranged vertically or horizontally offset from other ones of the radiating elements. US '732 also teaches the cross-connection of some of the radiating elements in one of the two columns with other radiating elements in the other one of the two columns, Sitimitiatv of the In

0012, T disclosure at an,stem cc- to etai

[(H) 13] The present disclosure thrther teaches d of system according to claim 1

Description of the Figures

[0014] Fig 1 shows an antenna system according to the present g an active antenna array [0015j Fitt 2 shows an tenna vi according to another aspectof the present disclosure.

6] 'Fig. 3 shows,an antenna system according to yet another ot the present (Tisch- SUM system according to yet another aspect of the present discio- [0017] Fig. 4 shows an 0 sure.

[0018] Figs 5A and 5 shows two examples of operation of an antenna system of the present disclosure, and Fig CC shows radiation beams and associated cell coverages provided with an antenna system of the present disclosure, [00191 Fig. SD rind SF. sho closure, operation of an the present dis- [0020] Fig, 6 show an example of phase shifter which can be used in an antenna sys present disclosure, Dctafledi)escrintjon of [0021] The invention w now be described the basis of the drawings. it will be under-stood that the embodiments and aspects of the invention described herein are only examples and do not limit the protective scope of the Claims in any way. The invention is defined by the claims and their references. It:will be understood that features of one aspect or embodiment of the invention can be combined with a feature of a, different aspects or aspects andlor embodiments of the inventie [0022] Fig. 1 shows an antenna system 1 with an active antenna array 10 f.ccording to one et of the disclosure, [0023] The antenn 20 na elements 30. column n and a second column 14 of anten- [0024] The antenna elements 30 of Fig.1 comprise colt rUing elements 33-I, 33-2,...$3-8 arranged in the first column 12 and second radiating elements 34-1, 34-2,...34-8 arranged in the second column 14. The first radiating elements 33-1, 33-2,...33-8 are arranged one above each other at vertical intervals at a distance dl from each other and the second ra-diating elements 34-1, 34-2,...34-8 are arranged one above the other at vertical intervals at a distance d2 from each other, The distances di and d2 are generally the same if both columns are designed for operation in the same frequency bands.

[0025] There eight antenna elementsthe first column 12 and a thither eight antenna elements arranged in the second column 1 in the example of FILL This is not limiting the awention, There will be at least three antenna elements 30 arranged in the first column 12 or the second c 30 in each of the fir -Ind generally between tbur and eighteen of the antenna elements an 12 or the second column 14.

[0026] The first radiating 1 3 and the second radiating elements 34- 1, 34-2, 34-8 are each ed from two dipole radiating elements. The first radiating ele-ments 33-1 13-2. 33-8 comprise first dipole radiating elements 33-11, 33-2 I_ 33-81 with a first polarisation P1 and second dipole radiating elements 33-12, 33-22,",, 33-82 with a second polarisation P2. The second radiating elements 34-1, 34-2,..., 34-8 of the second column 14 comprise third dipole radiating elements 3441, 34-21,..., 34-81 with a third polar- isation P3 and fourth dipole radiating elements 34-12, ,, 34-82 with a fourth polarisa-tion P4.

[002711 The first polarisation Pi Lo1ansation P2 are orthogonal polarisations, pref- erably at +45' and -450, The third polarisation P3 and the fourth polarisation P4 are orthogo- nal polarisations, preferably at +45' and The first polarisation PI and the third polarisa-don P3 preferably identical.

[0028] The first dipole radiating elements 13-11 having the same first polar-isation P1 are interconnected by a first feeding work 91 to create a first sub antenna array 12.-1. The second dipole radiating elements 33-12, 33-22,.., 33-82 having the same second polarisation P2 are interconnected by a second feeding network 92 to create a second sub an-tenna array 12-2. The third dipole radiating elements 34-11 - 34-81, having the same third polarisation P3, are interconnected by a third feeding network 93 to create a third sub ante/ma array 14-1 and the fourth dipole radiating elements 34-11, 34-21,..., 34-81, having, the same fourth polarisation P4, are interconnected by a fourth feeding network 94 to create a this'll) sub antenna array 14-1.

[0029] Hence, the antenna system 10 forms a two-column polarised antenna array with four independent sub antenna arrays 12-1, 12-2, 14-1, 14-2_ Four conesponding separate sub antenna array ports 13-1, 13-2, 11-3, 13-4, are provided for coupling the sub antenna arrays 12-1 144. 14-2 to one or more remote radio bead, as will be explained later in the dis-closure. The sub antenna arrays 12-1, 12-2, 14-1, 14-2 may be operated independently, [00301 A remote radio head (RREI) 40 is connected via an inteiface 60 to the first column 12 and the second column 14 of the antenna elements 30. The remote radio head 40 has a first channel 51 and a second chamiel 52, The first channel 51 comprises a first trrnsrnit sub-channel 51 r and a first receive sub channel SIR. The second channel 52 comprises a second transmit sub-channel 521 and a second receive sub-channel 52R, In one aspect of the disclo-sure, the first transmit sub-channel 511, first receive sub-channel 51R, second transmit sub-channel 521 and second receive sub-channel 52R are implemented for different transmission frequency hands and reception frequency bands, which are separated internally in the RRH 40.

[0031] The first channel 51 and the second channel 52 can be operated in the same frequency band in order to provide MIND capability.

[0032] The first channel 51 of the RRH 40 is coupled to a first duplex finer 81.

[0033] Duplex filters, in general, have three different ports and are configured to split a communication signal (common port) into a transmission signal portion (Tx-port) and a receiving signal portion (Rex-port). Duploxers are also working as combiner, de. the duplexers have the capability to combine a transmission signal and receiving signal to one communication signal.

[0034] The common port of the /duplex filter 81 is coupled to the first channel 51 of the HRH and one of the splittingteombining ports (Tx-port or Rx7port) of the duplex filter Si is coupled' to either One of the first sub antenna array port 13-1 and the second sub antenna army port 132. The other one of' the splitting/combining port (Rxliort Or Loper° of the duplex filter 81 is further coupled to either one of the third sub antenna array port 13-3 and the fourth sub antenna array port 13-4.

[0035] In the example of Fig. I, the duplex filter 81 is coupled to the first sub antenna array port 13-1 of the first column 12-1 having the first, polarisation pl by using the Tx-port of the duplex:filter 81 and the duplex filter 81 is coupled to the fourth glib, antenna array poet 13-4 of the fourth column 14-2 having the fourth polarisation P4 by using the Rx-port of the duplex filter 81.

[0036] The second channel 52 is connected to a second duplex filter 82. The common port of the duplex filter 82 is coupled to the second channel 52 of the RRH. One of the splitting/combining ports (Tx-port or Rx-port) of the duplex filter 82 is coupled to either one of the third sub antenna array port 13-3 and the fourth sub antenna array port 13-4 of the second column 14. The other one of the splitting/combining port (Fax-port or Tx-port) of the duplex fbrther coupled to el a array port 13-4 he third sub 3-3 and the fourth [0037] In the example of Fig.', the second duplex filter 82 is coupled to the first subulna: array port: 11-1 of the first column 12-1 having the first polarisation PI by using the Rix of the duplex filter 82 and is coupled the fourth sub antenna array port 134 of the fourth sub antenna array port 13-4 of the second column 14-2 having the fourth polarisation P4 by using the Tx-port of the duplex filter 82, [0038] In the example of Fig. 1, the duplex filters 81, 82 are coupled to the RIffi 40. Alter-the duplex filters S 82 can be integrated within the RRH 40.

[001391 The first channel 51 and the second channel 52 of the RH 40 provide telecommthgcation signals to the coupled first sub antenna. array 12-i and fourth sub antenna array 14,-2.

[0040] In one aspect of the disclosures the first column 12 of the antenna array system be used tiff relaying receive (Rx) Signals and the second column 14 of the antenna array 14: may be used for relaying transmission (Tx) signals fin one frequency band and ViCa versa. fit the example of Fig.l, the first column 12 is used for relaying the first transmit sub-channel 51T and the second rad6i.W. sub-channel 52R and the second column 14 is used for relaying the second transmit sub-channel 521' and the first receive sub-channel 51R.

[0041] By doing separation the second column 14 the isolation between the Rx-signals and the Tx-signals of one RUT channel is improved by at least 20dB, or even 30:dB if different polarisations are used for the sub-antenna array relaying the TN-signals and the sub antenna array relaying the Rx:-signals. Due to the improved:isolation be-is and the Tx signals of one RRTI channel, the requirements of the antenna system 10 regarding passive intermodulation products can be reduced. Passive intemiodulaP) is a form of distortion, whici, generates passive intermodulation products by the intermodulation of at least two transmission carriers of a telecommunications: signal in a specific frequency band, If these passive intermodulation products fall into the receiving frequency band of the respective channel with a certain signal hWet the receiver vilit be distorted. A designer of a circuit will therefore try and reduce the passive intennodination products by avoiding sources of FIM (non-linearities) or by improving the isolation between the receiving frequency band and the transmission frequency)and. Another improved isolation 'between the Rx-signals and the Tx-signals is that the duplex filters 8i, 82 connected to the RRI-1 40 can be designed with less complexity, because a lower isolation of the Rs:-iath is needed, f0 the okapi* of Fig. I, the second sub antenna array 12-2 Wi and the third sub antenna array 144 with the third port 13-3 are not coupled, to the RRII 40; These two unused second sub antenna array 12-2 and third Sub antenna array 144 can be coupled to an additional RRH (not Shown in a second network operator for provid-ing site sharing of the antenna, as described with reference to Fig. 3.

[0043] A horizontal distance d between a first radiating element in the first column 14 and a second radiating element 34-1 in the second column 14 is in one aspect between 0$ and 1.5 times the operating -velength of the telecommunications signals, 1) [0044] The first feeding network 91, the second feeding network 92, the third feeding network 93 and the fourth feeding network 94 of the first sub antenna array 124, the Second sub antenna array 12-1, the third sub:atutethila array 144, and the fourth saft antenna array 14-2 include each a phase shifter 71, 72, 73, 74 for providing an independent dowatilt for each an-tonna radiation beam of the corresponding 'first sub antenna army 12-1, second sub antenna array 124. 'third sub antenna array 144, and fourth sub antenna array 14-2, [0045] The phase shifters 71, 72, 73, 74 in the figures are shown schematically for convenience, Each radiator or at least a small sub group of radiators of the antenna element-are con-25 awed to a separate output of one phase shifter. This is well known for a person whc as shown in figure 6 showing the phase shifter 72 having eight outputs, each output being connected to a corresponding one of the second dipole radiating element 33-12, 33-22, , 33-82 of the second sub antenna array 12-2, [0046] As a non limiting example shown on Fig. A, the radhition beams formed from the first sub antenna array 12-1 and the second sub antenna array 12-2 by using the radiating elements 33-1 33-2, " 33-8 in the first column 12 may be adjusted ruth pendcntly of the other beams formed from the third sub antenna arrays 14-1 and the fourth sub antenna array 14-2, in the tilt ranges 0-12°, 0-14". 2-12", 214°, 2-16', 2-18° or similar. The radiation beams of the third sub antenna array 14-1 and the fourth sub antenna array 14-2 may be ju. the tilt ranges 6-18°, 6-20°, 2-18' or similar. The skilled person will understand that feeding network 91, the second feeding network 92, the third feeding network 93 and the fourth feed-work 94 coupled to the corresponding first sub antenna array 12-1, second sub antenna 12-1, third sub antenna array 14-1, and fburth sub antenna array 14-2 can provide a dif-ferent by adjusting via the corresponding phase shifter, the phase of the di leeihng signals of the respective radiating elements.

[0047] Fig. 5C shows two tilted radiating beams of the antenna system 10 as an example of an embodiment of the invention and a coverage area of a base Station site using three antenna systems 10 for serving three different communication cells A. B and C. The capacity of the communication cells A, B and C is doubled when using the aforementioned antenna systeth 10 per communication cell: As shown in the communication cell A, the two generated radiation beams allow a splitting-of the communication cell (so called vertical sector split) into two different coverage areas by using different tilt angles. Thereby the capacity is improved, for example doubled. The separation of the Tx-band and Rix-bandper ERRE-chiumel is beneficial for MIMO-purposes in the respective commtuaicationvell.

[0048] This may be the case when, as a non limiting example. the lirst radiating elements 33- 1, 33-2,...33-8 in first column 12 is operated so that the radiation beam has a first liii range of 4' and the second radiating elements 34-1. 34-2,...34-8 in the second column 14 is op-erated in a second tilt range of 14' +1-4°. The tilt ranges may overlap or may not overlap.

[0049] The antenna system E10 shownin Fig 1 assumes that all of the first radiating elements 33-1, 33-2,..., 33,8 in the first column 12 are connected to one feeding network and all of the second radiating elements 34--1, 34-2 in the Second colutm 14 are connecting to an-other feeding network. It would also be possible to "cross-connect" some of the first radiating elements 33-1, ... 13-8 to a first one of the feeding networks and others of the first radi34-2,, 34-8 to a second one of the feeding networks. This is shown in ating elements Figs, 5D and SE in which this cross-connection is shown schematically. In Fig. 50 a middle: one of the first radiating element 33-4 is connected to the second one of the feeding networks, whereas all of the r radiating elements 33-4 to 33-3 and 33-5 to 3 connected to the first one of the feeding networks. The corresponding second nt -34-4 in the second column 14 is connected to the first one of the feeding networks, wlemas of the radiating elements in the second column A ate connected to the second one of ing networks.

[0050] Similarly Fig. 5E, both of the topmost radiating elements 334 in the fiTstcolunnl 12 and 34-1 in the second column 14 are. connected to the same one of the feeding networks. Both of the hottommost radlatm4 elements 33-8 in ti*w first colunm 12 and 34-8n the second arm 14 arc connected to one of the feeding networks (and different to the top-most radiating elements 33-1 and 34-I).

[0051] The CTOSS-CAMOttiall of OtteS of the radiating elements 33-x and 34-x (x -example) can enable the half power beam width Of the radiation beams to be signif reduced.

[0052] Fig, 2 shows a further aspect of the antenna system 210, The antenna system 210 of * 2 differs from the antenna system 10 of Fig. 1 in that the antenna system, 210 comprises a* remote radio head 240 With a first channel 251; a second channel 252, a third channel 253; and a fourth channel 254, coupled to the four sub-antenna arrays 12-1, 144. 14,1 The elements which are identical in Figs. 1 and 2 have the same reference numbers, [0053] The remote radio headtiRRIB 240 is connected via an interface 260 to the fIrst column he second column 14 of the antenna system 210. The first channel 251 is coupled via a first duplex filter 281 to the first sub antenna any port 134 and to the fourth sub antenna array port 13-4. The second Channel 252 is coupled via a second duplex filter 282 to the sec- sub antenna *array port 13-2 and to the third sub antenna array port 13-3. The third chart- 253 is via a third duplex filter 283 to the second sub antenna array port 13-2 and to the third sub antenna array port 13-3. The fourth channel 254 is coupled via a fourth duplex 284 to the first sub antenna array port 1.3-i of the 'first column 12 and to the Efourth sub antenna army port 13-4 of the second column 14, [0054] The first channel 251 comprises First transmit and receive sub-channels; e.1 251R, 2511. The second channel 252 comprise second transmit and receive sub-channels 252R, 2521, The third channel 253 comprise third transmit and receive sub-channels 253R, 2531. The fourth channel 254 comprise fourth transmit and receive sub-channels 254R. 2541.

The transmit sub-channels 2511, 252T, 2531. 25411 and the receive sub-channels251R, 2512R, 253R, 254R are implemented by using ern Frequency hands which are separated by the external duplex filters 281, 282, 283, 284 or lly in the RICH 240 (not Shown), [00551 In the example of Vig.2, the first sub antenna array 12-1 is used ibt relaying the first:transmit sub-channel 2511 and the fourth receive sub-channel 254R. The second sub antenna array 12-2 is used for relaying the second transmit sub-channel 252T and the 0 sub-channel 253R The third sub antenna array 14-1 is used for relaying the third transmit sub-charnel 2531 and the second receive sub-channel 252R The fourth sub antenna array 14- 2 is used fin relaying the first receive sub-channel 251R and the fburth transmit sub-channel 2541.

1561 Two of channel 2512 second channel 252, third channel 253 and fourth nel 254 may operate at a first frequency band, whilst the other two el 251, second channel 252, third channel 253 and fourth channel, 254 may operate at a second fre- quency band, This Operation provides a dual i band:antenna, and still maintains 10 ca-pability for each one of the first and second:frequency bands, [0057] In the examples of and 2, duplex filters 81, 82, 281, 282, 283, 284 are provided which are independent from the RRI-1 40, 240. Alternately, duplex filters 81, 82, 281, 282, 283, 14 could also be implemented in the RR11.

[00 Fig, IshOWS another antenna array system, 110. The antenna system dif-fers from the antenna system 10 of Fig. I in that the antenna system 310 c remote radio head 42 with a third channel 53 and A fourth channel 54. The elements wine identical in Figs. t and 3 have the same reference numbers.

S seen on Fig. 3,the second remote radio head (RII) 42. is connected via an interface 260 to the first column 12 and the second column 14 of the antenna system 310. The third channel 53 comprises a third transmit sub;-channel 531 and a third receive sub Channel 53R. The fourth channel 54 comprises:a fourth transmit sub-channel 541' and a fourth receive sub Channel 54R [0060] The third channel.1s coupled via a third duplex filter 83 to the second sub antenna array port 13-2 and to the third sub antenna array port 13-3. The fourth enamel 54 is coupled via a fourth duplex filter 84 to the second sub antenna array port 13-2 of the first column 12 and to the third sub antenna array port 13-3 of the second column 14, [0061] The second sub antenna array 12-2 is used for relaying the third trans oh-channel 531' and the fourth receive sub ehanne154R, The third sub antenna array 14-1 is used for relaying the third receive sub-channel 53R and the fourth transmit receive sub-channel 54T.

[0062] The second remote radio bead 42 may operate at a different frequency range than the first remote radio head 40. The first remote radio head 40 and the second remote radio head 42 can be connected to different telecommunications operator networks. This enables the antenna system 310 of Fig. 3 to be commonly used by different ones of the telecommunications operators. Alternatively the same telecommunications operator could use the first remote radio head 40 and the second remote radio head 42 to feed the antenna system 310 with telecommunications signals of different protocols.

100631 Fig. 4 shows another antenna array system 410. The antenna system 410 of Fig. 4 dif fers from the antenna system 3 1 0 of Fig. 3 in. that the antenna system 410 comprises a first second diplexer 96. The elements which are identical in Figs. 3 and 4 have the same reference numbers.

[0064] In the further aspect of the disclosure shown figure, the first transmit sub-channel 51T and the second receive sub-channel 52R of the first remote radio head 40 as well as the third transmit sub channel 531' and the fourth receive sub channel 54R of the second radio head 42 are coupled to a first diplexer 95. The first receive sub channel 51R, the second transmit sub channel 521' of the first remote radio head 40 as Well as channel 53R and the fidurth transmit sub channel 541 of the second radio to a second diplexer 96. did receive sub-4' are led [0065] The output of the first diplexer 95 feeds the st sub antenna array 12-1, and the out-30 put of the second diplexer 90 feeds the fourth sub antenna array 14-2 of the second column 14. This arrangement provides a dual band antenna system 410 because the RREls are working in different frequency bands.

[00661 The skilled person will understand that e examples of the antenna systems in Figs -4 may be used for MINIO applications or for providing a vertical sector split as shown on lqnrc 5A-5(I. A vertical sector split generates two vertical independent radiation beams for one sector of one of the network operators. By using the technique of vertical sector splitting, the capacity of the sector served by the network operator can be increased, M particular doubled.

-Nunierais 12 first counin 12-1 first sub antenna array 12-2 second sub antenna array 14 second column 14-1 third sub antenna array 14-2 second sub antenna array 11-1 4 sub antenna array port 30 antenna clement 33-1 to -8 first radiating elements 33-11 to -81 first dipole radiating element 33-12 to -82 second dipole radiating element 34-1 to -8 second radiating elements 34-11 to-81 third dipole radiating element 34-12 to -82 fourth dipole radiating element remote radio head 51(251 first cliarinel 51TiR 251T/R transmit/receive sub-channel 52/252 second channel 52T/R, 2T/R transmit/receive sub-channel 53/953 third channel 53T/R, 2 T/R transmit/receive sub-channel 54/954 fourth channel 541/R., 254- transmit/receive sub-channel 71, 72, 73.74 phase shifters 91 first feeding network 92 second feeding network 93 third feeding network 94 fourth feeding network first diplexcr 96 second diptexer