DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0099] FIGS. 1 and 2 illustrate a preferred embodiment of a flat-panel repeater, having a pair of flanged radomes 10 and 11 on opposite sides of a choke frame 12 . Adjacent the inside surface of the radome 10 is a dielectric sheet 13 carrying four printed dipoles 14 that form the mobile-facing antenna for the mobile side of the repeater. The electronics for connecting the antenna to the necessary diplexers, filters, and power amplifiers are contained within a metal housing 15 , and the antenna sheet 13 is fastened to one side of the housing 15 . The antenna feed 16 is connected directly to one of the diplexers in the electronic circuitry, which will be described in more detail below. The housing 15 is captured within the choke frame 12 , which forms multiple, spaced, concentric fins 72 a - 72 d for improving the side-to-side (antenna-to-antenna) isolation of the flat-panel repeater, thereby improving the gain performance or stability margin (the difference or safety margin between isolation and gain). The structure of the fins 72 a - d will also be described in more detail below.
[0100] The antenna elements on the opposite side of the repeater are mounted adjacent the inside surface of the radome 11 . Thus, a pair of dipoles 14 a are printed on a dielectric sheet 13 a to form the base-station-facing antenna for the base-station side of the repeater. The antenna feed 16 a is connected directly to one of the diplexers in the electronic circuitry, as described in more detail below. The dielectric sheet 13 a is fastened to the opposite side of the metal housing 15 from the sheet 13 . As can be seen in FIG. 2 , the dipoles 14 are orthogonal to the dipoles 14 a to improve isolation between the two antennas.
[0101] To facilitate mounting of the repeater on a flat surface, a mounting bracket 17 has a stem 18 that fits into a socket 19 in the frame 12 . The bracket 17 has several holes through it to receive screws for attaching the bracket 17 to the desired surface. Electrical power can also be supplied to the repeater through power supply lines (not shown) passing through the mounting bracket 17 and its stem 18 into the frame 12 . The interface between the frame 12 and the bracket stem preferably allows rotation between the frame 12 and the mounting bracket 17 in successive angular increments, such as 5 ′ increments, to facilitate precise positioning of the repeater. For example, the repeater might be rotated through successive increments while monitoring the strength of the received and/or transmitted signals, to determine the optimum orientation of the repeater, e.g., in alignment with a broadcast antenna whose signals are to be amplified and re-broadcast. Conventional detents can be used to indicate the successive increments, and to hold the repeater at each incremental position until it is advanced to the next position.
[0102] As can be seen in FIG. 1 , the flat-panel repeater comprises a closely spaced stacked array of planar components that form a compact unit that can be easily mounted with the antennas already aligned relative to each other. The height and width of the unit are a multiple of the thickness dimension, e.g., 7 to 8 times the thickness. The thickness dimension is preferably no greater than about six inches, and the greater of said height and width dimensions is preferably no greater than about two feet. It is particularly preferred that the thickness dimension be no greater than about three inches, and the greater of said height and width dimensions no greater than about 1.5 feet. Most preferably, the thickness dimension is no greater than about two inches, and the greater of the height and width dimensions is no greater than about one foot.
[0103] FIGS. 3 and 4 illustrate a flat-panel repeater 20 having a pair of flat radomes 21 and 22 on opposite sides thereof. Each radome 21 and 22 covers one or more antenna elements for receiving and transmitting signals on opposite sides of the repeater. In the illustrative embodiment, the antenna elements are the patches of patch-type antennas, but it will be understood that alternative antenna elements such as dipoles or monopoles may be used. As can be seen in FIG. 4, a pair of patches 23 and 24 are printed on a dielectric plate 25 mounted adjacent the inside surface of the radome 21 . The dielectric plate 25 seats in a recess 27 formed by a metal plate 28 that also forms a ground plane for the patches 23 and 24 . The plate 25 seats on multiple plastic standoffs 27 a connected to the plate 28 within the recess 27 , and a pair of coaxial connectors 27 b extend through he plate 28 for connection to the patches 23 and 24 . The inner conductors of the connectors 27 b are connected to the patches 23 and 24 , while the outer conductors are connected to the ground plane 28 . The opposite ends of the connectors 27 b are connected to the RF circuitry on the board 36 . Because the dielectric plate 25 is recessed within the ground plane, the patches 23 and 24 are substantially flush with the surface of the ground plane.
[0104] It can be seen that the ground plane formed by the metal plate 25 is considerably larger than the antenna patches 23 and 24 , and the patches are positioned in the central region of the ground plane. These features offer significant advantages in improving the isolation between the two antennas, which in turn improves the gain performance or stability margin of the repeater, as will be discussed in more detail below. In general, the ratio of the total ground-plane area to the central area occupied by the antenna elements is in the range of about 2 to 5, and is preferably about 5, to achieve the desired isolation.
[0105] The repeater 20 includes a three-part frame, consisting of a central frame member 29 and a pair of RF-choke frames 30 and 31 attached to opposite sides of the central member 29 . The periphery of the ground-plane plate 27 is captured within a slot in the inner periphery of the choke frame 30 . The central frame member 29 is essentially closed on one side by an integral wall 32 that forms a bottom ground plane, and the interior of the member contains several electronic units (e.g., printed circuit boards) and a power connector 33 . A top ground-plane plate 34 closes the open side of the frame member 29 , and is attached to a peripheral flange 35 on the frame member 29 . A second group of electronic units are mounted on a board 36 attached to the outside of the ground-plane plate 34 .
[0106] The antenna elements on the opposite side of the repeater are mounted adjacent the inside surface of the radome 22 . Thus, a pair of patches 37 and 38 are printed on a dielectric plate 39 seated in a recess 40 formed by a metal plate 41 that also forms a ground plane for the patches 37 and 38 . As can be seen in FIG. 4 , the patches 23 , 24 are orthogonal to the patches 37 , 38 to improve isolation between the antennas on opposite sides of the repeater. The periphery of the ground-plane plate 41 is captured within a slot in the inner periphery of the second choke frame 31 . The patch plate 39 seats on multiple plastic standoffs 40 a connected to the plate 41 within the recess 40 , and a pair of coaxial connectors 40 b extend through the plate 41 for connection to the patches 37 and 38 . The inner conductors of the connectors 40 b are connected to the patches 37 and 38 , while the outer conductors are connected to the ground plane 41 . The opposite ends of the connectors 40 b are connected to the RF circuitry on the board 36 . Multiple gaskets G are provided for sealing purposes.
[0107] An antenna is (simplifying somewhat) a path by which electrons get accelerated back and forth (i.e. a “race-track”). For example, in a dipole antenna, electrons accelerate from one end, towards the center (where they have the greatest velocity), then de-accelerate towards the other end (where the velocity is the slowest). They then turn around and accelerate back the other way. They do this at the rate of the resonant frequency of the antenna. The feed point of the antenna (for a dipole, at the center) is the position in which the electrons are moving the fastest. Thus, voltage (potential) of the antenna is tapped from this position. Electromagnetic energy therefore radiates from the ends of an antenna element (dipole or patch) in the direction of the accelerating electrons. This direction is called the antenna polarization (direction). Displacement currents (virtual electrons) therefore go from one end of the dipole, curve out in space, and terminate at the other end of the dipole. For two adjacent antennas, oriented in the same direction, where one is transmitting (active) and the other is receiving (passive), the active antenna pushes virtual electrons into space which terminate on the passive antenna. These virtual electrons then force the actual electrons on the surface of the passive antenna to accelerate, and induce a potential at its feed point. However, if the two antennas are not oriented in the same direction (being orthogonal . . . or perpendicular; for instance) then the active antenna cannot accelerate electrons on the other (passive) antenna. The “race-track” on the passive antenna is extremely short. These antennas are considered orthogonal, and therefore do not couple. Orthogonal antennas, on opposite sides of the repeater, do not couple and therefore appear isolated from each other. Thus, the system gain is increased without inducing ringing.
[0108] The RF electronic circuitry and antennas for the repeaters of FIGS. 1 - 4 is illustrated in more detail in FIGS. 5 - 8 . Two different system architectures are shown in FIGS. 5 and 6 . FIG. 5 shows an architecture for a two-antenna system, in which each of two antennas 52 and 54 operates in both the transmit and receive modes. For example, the first antenna 52 might be used to receive incoming RF signals from, and transmit signals to, a transmitter or another repeater, that is, in the link mode. The other antenna 54 would then be utilized in the broadcast/repeat mode to transmit signals to, and receive signals from, the user equipment, such as a remote handset or terminal, or to transmit a signal to a further repeater in a system using multiple repeaters to broadcast or distribute signals.
[0109] An electronics module 60 connected to both antennas 52 and 54 includes a pair of frequency diplexers (D) 61 , 62 to effectively connect received signals from either antenna to only the receive circuitry for that antenna and not to the transmit circuitry for that same antenna, and to effectively connect transmit signals from the transmit circuitry to only the antenna and not to the receive circuitry for that same antenna. For example, RF signals received by the antenna 52 are routed through the diplexer 61 to a receive path that includes a filter 63 to attenuate the reverse link band, an amplifier 64 to amplify the RF, and then another filter 65 to protect the amplifier 64 from signal power on the other path. The second diplexer 62 then delivers the signal to the antenna 54 which re-transmits the amplified signal. In the reverse direction, the antenna 54 receives signals that are fed through the diplexer 62 to a second path including similar filters 66 , 67 and a similar amplifier 68 which operate in the same manner as the first circuit to feed signals through the diplexer 61 to be transmitted at the antenna 52 .
[0110] FIG. 6 shows a four-antenna architecture that includes two pairs of antennas 52 a , 54 a and 52 b , 54 b on opposite sides of the repeater. The antennas 52 a , 52 b on one side may be used for the link mode, as described above, one as the downlink antenna and one as an uplink antenna. Similarly, the two antennas 52 b , 54 b on the other side may be used in the broadcast/repeat mode, as described above, one as an uplink antenna and one as a downlink antenna. Similar electronic circuits or paths including filters and amplifiers are interposed between the respective pairs of antennas 52 a , 54 a and 52 b , 54 b . However, because separate pairs of antennas are provided, no frequency diplexers are required in this case.
[0111] The filters 63 , 65 , 66 , and 67 are band pass filters selected to reduce the out-of-band signals. For a PCS-based system, the typical band pass bandwidth is approximately 15 MHz, commensurate with the bandwidth of PCS bands C, D, E, F, etc. Cut off and roll-off are performance and specification oriented, and depend on the circuit design.
[0112] In one embodiment, the amplifiers 64 , 68 comprise relatively low power, linear integrated circuit chip components, such as monolithic microwave integrated circuit (MMIC) chips. These chips may comprise chips made by the gallium arsenide (GaAs) heterojunction transistor manufacturing process. However, silicon process chips or CMOS process chips might also be utilized.
[0113] Some examples of MMIC power amplifier chips are as follows:
[0114] 1. RF Microdevices PCS linear power amplifier RF 2125P, RF 2125, RF 2126 or RF 2146, RF Micro Devices, Inc., 7625 Thorndike Road, Greensboro, N.C. 27409, or 7341-D W. Friendly Ave., Greensboro, N.C. 27410;
[0115] 2. Pacific Monolithics PM 2112 single supply RF IC power amplifier, Pacific Monolithics, Inc., 1308 Moffett Park Drive, Sunnyvale, Calif.;
[0116] 3. Siemens CGY191, CGY180 or CGY181, GaAs MMIC dual mode power amplifier, Siemens AG, 1301 Avenue of the Americas, New York, N.Y.;
[0117] 4. Stanford Microdevices SMM-208, SMM-210 or SXT-124, Stanford Microdevices, 522 Almanor Avenue, Sunnyvale, Calif.;
[0118] 5. Motorola MRFIC1817 or MRFIC1818, Motorola Inc., 505 Barton Springs Road, Austin, Tex.;
[0119] 6. Hewlett Packard HPMX-3003, Hewlett Packard Inc., 933 East Campbell Road, Richardson, Tex.;
[0120] 7. Anadigics AWT1922, Anadigics, 35 Technology Drive, Warren, N.J. 07059;
[0121] 8. SEI Ltd. P0501913H, 1, Taya-cho, Sakae-ku, Yokohama, Japan; and
[0122] 9. Celeritek CFK2062-P3, CCS1930 or CFK2162-P3, Celeritek, 3236 Scott Blvd., Santa Clara, Calif. 95054.
[0123] FIGS. 7 and 8 show the choke frame of FIGS. 1 and 2 in more detail. This frame is generally rectangular in configuration and includes multiple fins 70 extending orthogonally outwardly from opposite sides of central flat support members 71 and 72 . As can be seen most clearly in the sectional view in FIG. 8 , the fins 70 become progressively shorter in the axial direction, and the space between adjacent fins becomes progressively smaller, proceeding from the radially outermost fins 70 a to the innermost fins 70 d . The fins preferably have height and spacing dimensions related to one-fourth wavelength at the center frequency of the frequency band being amplified and re-transmitted by the repeater, e.g., the height or projection of the fins relative to the sides of the housing may be on the order of a quarter wavelength. In addition, strips of radio frequency absorber material 74 may be located intermediate some or all of the fins 70 about the peripheral surfaces of the main body of the choke frame. Absorber material is typically a low density dielectric loaded with conductive particles or fibers of carbon or metal, and can even be “tuned” to absorb certain frequencies more than others.
[0124] FIG. 9 illustrates in more detail the peripherally extending fins 73 that form the RF choke between the antennas on opposite sides of the flat-panel repeater of FIGS. 3 and 4 . These fins 73 comprise relatively thin strips of conductive material located around the periphery of the RF choke frame. FIGS. 10 - 13 illustrate alternate embodiments of RF chokes of various forms.
[0125] In FIGS. 10 and 11 , the RF choke is formed by a series of concentric annular rings 75 which extend generally orthogonally relative to the plane of the antenna and around the periphery of the antenna, in contrast to the radially extending fins described above. As can be seen mostly clearly in the sectional view of FIG. 11 , the choke rings 75 are formed by a corrugated metal annulus in which the outer wall 75 a is slightly shorter than the first full corrugation crest 75 b in the axial direction, and then the successive corrugation crests 75 c and 75 d become progressively shorter in both the axial and radial directions.
[0126] The circular choke configuration of FIGS. 10 and 11 has the advantage of providing feedback paths of equal length between all points on the peripheries of the antennas on opposite sides of the repeater. Unwanted feedback occurs via surface currents on the outside surfaces of the panel, and path lengths that are odd multiples of one-half wavelength produce cancellation of the unwanted surface currents. The circular configuration facilitates a choice of dimensions that achieve the desired cancellation of feedback currents because of the uniformity of the lengths of the feedback paths between the two antennas with such a configuration. In general, the repeater is sized and configured for a selected frequency band having a predetermined center frequency and wavelength “X”; the height, width and thickness dimensions of the repeater are selected so that feedback energy at the wavelength “X” travels a feedback path of predetermined length around the repeater to improve the side-to-side isolation.
[0127] FIGS. 12 and 13 illustrate a circular configuration for a choke structure similar to that shown in FIGS. 8 and 9 . Multiple fins 80 extend orthogonally outwardly in the axial direction from opposite sides of central flat support members 81 and 82 . As can be seen most clearly in the sectional view in FIG. 13 , the fins 80 become progressively shorter in the axial direction, and the space between adjacent fins becomes progressively smaller, proceeding from the radially outermost fins 80 a to the innermost fins 80 d.
[0128] In an alternative embodiment, a reduced surface wave (RSW) type of antenna structure might be utilized in place of the patch antennas shown in the prior figures. FIGS. 14 and 15 are a side sectional view and a top plan view of one example of a probe-fed, shorted annular ring, reduced surface wave patch antenna 460 . An RSW patch antenna element, is simply a patch that focuses more energy in the directed area, and not to the sides near the ground plane. There are many types of RSW patches, but the most common is a recessed patch inside a partial cavity. The cavity walls act as a field suppressor, and “catch” field lines that are directed to the sides of the patch, rather than in a direction perpendicular to the patch and ground plane. If both patches (on opposite sides of the repeater) are RSW patches, then they have reduced coupling (i.e. greater isolation), which allows the system active gain to be increased.
[0129] RSW microstrip antennas produce only a small amount of surface-wave radiation. In addition, if printed on electrically thin substrates, these antennas only weakly excite lateral waves (space waves that propagate horizontally along the substrate interface). As a result, these antennas do not suffer from the deleterious effects of surface and lateral wave scattering. These characteristics make the RSW antenna ideal for applications where the supporting substrate or ground plane of the antenna is small, in which case diffraction of the surface and lateral waves from the edges of the structure may be quite significant for conventional microstrip patch antennas. RSW antennas may also be useful for array applications, where the presence of surface and lateral waves for conventional patch radiators produce significant mutual coupling and may lead to scan blindness.
[0130] For a given size antenna element (patch, dipole, etc.), increasing the size of the ground plane behind the element reduces the Front to Back (F/B) ratio of the antenna. More specifically, the larger the ground plane, the less energy radiated to the back side. Thus, increasing the size of the faces of the side-to-side repeater reduces the amount of energy that each face radiates to the backward face. Another way of explaining this is that by increasing the size of the repeater, the lower the coupling between the antennas on opposite sides of the repeater (i.e. patches). This therefore increases the isolation between the antennas, and allows the active gain for the system to be increased. However, where the size of the ground plane is limited by other considerations, the RSW patch technology may be employed.
[0131] A preferred RSW design is the Shorted-Annular-Ring Reduced-Surface-Wave (SAR-RSW) antenna. One example of this type of antenna, shown in FIGS. 14 and 15 , is a conventional annular ring microstrip antenna 462 with an inner boundary 464 short-circuited to a conducting ground plane 466 . The outer radius dimension is chosen to eliminate surface-wave excitation from the equivalent ring of magnetic current at the outer edge of the antenna that corresponds to the TM 011 cavity patch mode. (The modes are denoted using the notation TM φρ .) The inner radius is chosen to make the patch resonant at the design frequency.
[0132] FIGS. 16 and 17 diagrammatically illustrate repeater modules 50 and 50 a with patch antennas that correspond respectively to the systems described above. In these examples, microstrip patches are used for the antenna elements 52 , 54 ( FIG. 16 ) and 52 a , 52 b , 54 a , 54 b ( FIG. 17 ). The module/box or housing 50 , 50 a may contain a DC power supply or DC power converter, amplifiers, filters and diplexers (if required), as described above. The electronics may be discrete parts, connected together via SMA connectors. For lower power systems, the electronics can be surface mount PCB. A small lamp, LED, or other display element 100 can be used with appropriate RF power sensing electronics 80 (see FIGS. 5 and 6 ) to aid the provider/user/customer in orienting the unit or module 50 or 50 a with a link antenna directed/pointed towards a base station, such that sufficient signal power is being received, i.e., at or above some predetermined threshold.
[0133] FIG. 18 illustrates an approach which uses an array of antenna elements in order to increase the passive gain. The example shown in FIG. 18 uses two columns of patch array antenna elements on one face of the module, designated by reference numerals 54 a through 54 h . The antenna patches 54 a through 54 d are designated as receive (Rx) elements in the embodiment shown in FIG. 18 , while the antenna elements 54 e through 54 h are designated as transmit (Tx) elements in this embodiment. It will be appreciated that a similar array of antenna elements, corresponding to the antenna elements 52 of the prior embodiments, are mounted to the opposite face (not shown) of the module 50 b of FIG. 18 . Moreover, fewer or more array elements might be utilized in other patterns than that shown on FIG. 18 , without departing from the invention.
[0134] In the embodiment shown on FIG. 18 , the use of four elements, which are summed together in an array, achieves approximately four times (6 dB) the gain of a single receive or transmit element. Thus, with four elements also on the opposite face (not shown), this adds a total of 12 dBi of additional passive gain to the system, which can be used to reduce the required active gain by as much as 12 dB and also to reduce the required isolation by as much as 12 dB. While the near-field wave mechanics might not permit a full 12 dB to be achieved, nonetheless, some considerable improvement can be expected from this approach. The vertical beam width of the system will be reduced somewhat by this approach.
[0135] The antennas on opposite sides of the repeaters described above are “fixed” in position and orientation to assure maximum isolation between the antennas and to receive and transmit a given signal, and therefore maximize system gain. This isolation between antennas is controlled/maximized (and mutual coupling minimized) in the following ways:
[0136] a) The two antennas (or sets of antennas) are positioned such that for each, the F/B ratios sum to a maximum. For example, for a perfectly rectilinear module, the two antennas (or sets of antennas) each face oppositely by 180 degrees, or within an acceptable tolerance.
[0137] b) The two antennas of each path, are polarized in mutually orthogonal (perpendicular) directions, which further reduces the mutual coupling (increases the isolation) by roughly 20 to 30 dB.
[0138] c) Electromagnetic choke or shunt elements are provided on the edges or borders of the module or housing structure to absorb (shunt) power to ground. Alternatively, the four sides of the housing (i.e., excluding the two sides on which the antennas are mounted) may be composed of metallic material and grounded so as to shunt stray electromagnetic energy to ground.
[0139] Design of the antennas, beams, and (control of) F/B ratios assures adequate isolation between the two opposing antennas (or antenna sets). The antennas'F/B ratios or isolation is the largest limiter for the total system gain. If desired, the isolation can be further improved by having the wireless connection to the base station on a different frequency band from the remote connection.
[0140] The above described repeater modules can be used in a number of applications, a few examples of which are as follows.
[0141] 1) Indoor Repeater (see FIG. 19 )
[0142] The flat-panel repeater can be mounted on a wall or window, at or near a location where the RF signal power from a nearby base station is at its maximum power level (within the building). Power for each repeater can be supplied via either a 120-volt cord and plug 102 , or with a 120-volt plug connection 104 , built directly into the repeater (see FIGS. 20 and 21 ). Both allow very simple installation, by the customer. Generally, the RF signal is received, at a power level above the noise floor, from a nearby base station (with the module placed in a location facing the base station), and the repeater re-radiates the (amplified) RF signal into the building. Additionally, signals from remote units (handsets/cellphones) within the building are received by the repeater, amplified, and re-radiated back to the base station 200 .
[0143] 2) Daisy-Chained Indoor Repeater (see FIG. 22 )
[0144] FIG. 22 shows a plurality of flat-panel repeaters 50 or 50 a placed at various locations within a building, “daisy chained” together, to provide greater coverage within the building. This aids in providing coverage to the side of the building opposite to the base station, or any other RF null or “blank” areas within the building. In this way, the provider or customer can cheaply and easily install two or more repeaters, to provide coverage to various areas of the building, such as the side opposite the side nearest the base station, where the RF signal level (from the base station) has low Signal to Noise (ratio), or where there is no signal at all.
[0145] If it is desired to distribute multiple wireless services within a building, such as PCS, MMMDS, LMDS, wireless LAN, cellular telephone, etc., all such signals may be supplied from their receiving antenna(s) to an Ethernet hub before entering the daisy-chained indoor repeaters, as illustrated in FIGS. 23 a and 23 b . A separate antenna 110 and electronic circuits 111 are provided for each wireless service, and all the circuits 111 are connected to an Ethernet hub 112 . Each of the circuits 111 includes a frequency converter for converting signals from the frequency used by the wireless service to an Ethernet frequency. The Ethernet hub 112 controls the forwarding of the signals from the multiple wireless links to the single wired connection from the Ethernet hub 112 to an indoor flat-panel repeater 113 , which then relays those signals on to other repeaters such as repeaters 114 and 115 located throughout the interior of the building.
[0146] Each of the repeaters 114 and 115 has two antennas on the downlink side. Specifically, a first antenna 114 a on the repeater 114 is designed to produce a beam 117 aligned with the next repeater 115 , while a second antenna 114 b produces a beam 118 that extends laterally through the adjacent portion of the interior of the building to reach all the users in that portion of the building. For user devices that are not part of an Ethernet, such as PCS subscriber units, the signals from the second antenna 114 b are received by an Ethernet-to-PCS conversion unit 119 shown in more detail in FIG. 23 b . This conversion unit includes an antenna 119 a that complies with the IEEE 802.11 standard, a DSP 119 b , an RF conversion circuit 119 c for converting the frequency of received signals to the PCS frequency, and a PCS antenna 119 d for transmitting the converted signals to PCS users in the building. Of course, the conversion unit 119 also works in the reverse direction, receiving PCS signals from subscriber units at the antenna 119 d , converting them to the Ethernet frequency in circuit 119 c , and transmitting them from antenna 119 a to the repeater 114 for re-transmission back to the repeater 113 and the Ethernet hub 112 which selects the appropriate circuit 11 and antenna 110 .
[0147] 3) Outdoor Null Fill Repeater
[0148] A single flat-panel repeater can be installed on a tower, instead of a more conventional repeater installation requiring discrete antennas. This provides a smaller, more economical package, and less labor (time) and effort in orienting the antennas to assure adequate isolation between the antennas.
[0149] 4) Outdoor Repeater to Building
[0150] A single flat-panel repeater can be installed on a tower, in the same fashion as above, realizing the same benefits.
[0151] The applications mentioned above in 1)-4) are independent of frequency band. That is, any of these applications might be used in any frequency band, including, but not limited to, the following:
[0152] a) Cellular (800 MHz band)
[0153] b) PCS (1800 and 1900 MHz bands)—(Personal Communications Service)
[0154] c) GSM (900 and 1800 MHz bands)—(Global System for Mobile communications)
[0155] d) MMDS (2500 MHz band)—(Multi-channel Multipoint Distribution Service)
[0156] e) LMDS (26 GHz band)—(Local Multipoint Distribution Service)
[0157] f) Bluetooth Applications (2400 MHz band)—(Bluetooth is the name of a wireless protocol standard, created by Ericsson)
[0158] g) Indoor Wireless LANs (2400 MHz band)—(Local Area Network)
[0159] h) 3G (3rd Generation PCS systems) at 1900 MHz (U.S.) and 1800-2200 MHz (Europe)
[0160] If it is desired to increase the wide-angle coverage of the signals re-transmitted by the repeater, one side of the repeater may be provided with multiple antennas oriented in different directions.
[0161]