SELF-POWERED AMPLIFIER DEVICE FOR TRANSCEIVER ANTENNA

Description

SELF-POWERED ANTENNA AMPLIFIER DEVICE TRANSCEIVER On behalf of: HI-TE Srl with headquarters in: Piazza Cesare Battisti, 116 – Goro (FE) DESCRIPTION OF THE INVENTION The present invention falls within the technical sector relating to radio frequency telecommunications. In particular, the invention relates to a low-frequency amplifier device self-powered radio frequency noise amplifier (LNA – “Low Noise Amplifier”) for transceiver antennas. Civilian and military radiocommunication systems make use of antennas, also portable, for voice and data connections with other terrestrial stations or satellites. The radio link between two stations is much more stable and reliable. the more intense the signals arriving at the receiver input are high, so as to emerge sufficiently from the background noise produced essentially from the receiver electronics. If the level of signals received by the antenna and, subsequently, by the receiver a radio station, it is very low, and still close to the threshold of sensitivity of the receiver itself, a risky situation is created for the connection. In these cases the useful signal can be detected in a intermittent and therefore the communication appears disturbed to the point of being incomprehensible; or, especially in the case of digital communications, the signal can be revealed with errors in the received data, which force the continuous retransmission of data packets and thus a significant loss of connection efficiency. The consequences of this problem can be potentially serious, especially in cases where radio communications represent an essential resource for the safety of the operator or for the success of an operation. This is the case, for example, in the military field, of communications that occur over an operating field between mobile stations installed on vehicles or used by the military, or between mobile and satellite stations, where the stability and reliability of transmissions in any situation represent requirements of the utmost importance. The safety conditions of the connections are guaranteed, as well as from the performance of the transceiver equipment, from the characteristics of the antennas used. Normally the size of the antenna is associated with the its reception and transmission capacity (gain), but in all cases where communications take place on the move, for example with stations installed at on board land, sea or air vehicles or via equipment individual portable transceivers, the antennas must have dimensions relatively modest, and in general cannot afford to earn directivity, as they are necessarily foreseen for use in conditions in which it is not possible to point to the correspondent, regardless of whether it is a ground or satellite station. In these cases it is advisable to increase the reception gain by means of a low noise amplifier device, usually referred to as LNA (Low Noise Amplifier). Noise Amplifier), to be placed between the antenna and the radio. This device amplifier has the sole purpose of amplifying the received signal before its application to the input stage of the receiver, so as to improve the signal to noise ratio for the benefit of a better reception margin. In in some cases the aforementioned LNA is inserted inside the antenna itself receiver, thus avoiding the presence of an additional external device, and so as to minimize the attenuation loss in the section of the line transmission placed between the antenna and the LNA input, attenuation which would partially nullify the low-noise amplification action of the same LNA. Since the LNA is a unidirectional device that amplifies the very weak signal coming from the antenna and directed towards the receiver, it must be excluded in the phase in which the radio transceiver is put into transmission, to avoid its damage by the high power signal that, emitted by the radio, travels towards the antenna, used in this case in transmission. In currently adopted solutions bypassing the LNA, i.e. creating a path for the RF signal that you pass outside the LNA without entering it from its exit door, it is made with electromechanical relays which are activated during the reception phase powered by a current supplied by the radio itself through the connector antenna and applied to the LNA via the RF cable and a circuit extractor. At this stage, the same current is also applied to the chip. amplifier which represents the active part of the LNA. In the phase of transmission, the radio stops supplying direct current through the RF antenna connector, consequently the relays remain de-energized and they return to their resting position, which creates the bypass RF path of the LNA. This solution, which currently represents the state of the art in portable antennas equipped with LNA amplifier, has several disadvantages: a) the switching time from RX to TX and vice versa depends essentially on the mechanical switching time of the relays, which on average involves a delay of 2 milliseconds in the transition between the two states; this delay could, in in cases of digital communications, lead to packet loss; b) since in the case of digital communication continuous switching is foreseen between RX and TX for sending the “acknowledgements” required by the protocols communication, although the switching speed of electromechanical relays allows for correct operation of the connection, the relays are subjected to continuous switching, with annoying “buzzing” noise, which in case of operations in critical conditions can be dangerous as they can easily detectable; c) the continuous switching of the relays, in addition to causing the aforementioned noise, leads to a rapid deterioration in the quality of the contacts which, especially in cases where the switching occurs with the presence of RF power signal, they oxidize and become unreliable. To solve the whole series of problems described, it is necessary to use switching devices for bypassing the LNA in the transmission phase that they are not of the electromechanical type, but of the electronic type, extremely faster. These devices are normally available on the market and widely used in the field of RF signal switching, but They present an insurmountable problem when used with radio equipment transceivers that make available a power supply current only in the receiving state. In fact, these devices require power for everything the usage time, regardless of whether the radio is in the standby state reception or transmission, requiring one or the other to be kept in conduction the other of the doors through which they route the signal in reception and in transmission. When the power fails in the transmission state of the radio, therefore, the power supplied by the radio itself could not flow regularly through the bypass pathway outside the LNA, as This is not provided. Not only that: the switching devices electronics would be placed in an indefinite state, in which the behavior when passing the RF power signal which, with all likely, it would permanently damage the switching device or itself or the LNA. The purpose of the present invention is to provide a device self-powered low-noise radio frequency amplifier for antenna, usable in particular in association with radio equipment designed to provide DC power supply to the antenna only during reception phases of the RF signal. In this regard the amplifier device is equipped with means for powering the devices during use of the transmitting antenna switching electronics that bypass the LNA, without requiring power sources power supplies external to the antenna itself. Another object of the invention is to provide a device low noise radio frequency amplifier provided with means for maintain the above power supply of electronic switching devices even in transitional situations between the reception and transmission states and vice versa. A further object of the invention is to provide a configuration radio frequency signal circuit from the radio equipment to the antenna, and from there to the radio equipment through the aforementioned LNA, capable of ensuring the power supply of electronic switching devices even during the reception phase. These and other purposes are fully achieved by a device self-powered amplifier for transceiver antenna, which includes: − a low-noise RF amplifier, designed to amplify a signal RF injected into its own input and make it available to a own exit; − a first electronic switch, electrically connected to a radiating group, at the input of the RF amplifier and to a line of bypass signal; − a second electronic switch, electrically connected to a input / output terminal by means of a signal line, to the RF amplifier output and to the bypass signal line; - power supplies for the first and second electronic switches, comprising an RF / DC converter connected to the signal line, capable of taking a portion of the RF power signal from it during the transmission phases and convert it into direct current, and also connected to the first and second electronic switches for provide them with electrical power during the aforementioned phases of transmission. The features of the invention will be evident from the following description of preferred embodiments of an amplifier device for self-powered antenna (LNA), in accordance with the content of the claim main No. 1 and with the aid of the attached drawing tables, in which: − Figure 1 schematically illustrates a transceiver antenna portable, equipped with a self-powered LNA device made according to the invention; − Figure 2 shows a block diagram of the LNA device self-powered of Figure 1, made according to a preferred form of realization of the invention, in which the paths of the RF signal and power lines of electronic switches with the antenna is receiving; − Figure 3 illustrates the block diagram of Figure 1 in which the following are highlighted: RF signal paths and switch power lines electronic with the antenna in transmission phase; − Figure 4 illustrates the block diagram of Figure 1, in which are the paths of the RF signal and the lines are highlighted in solid lines power supply of electronic switches with the antenna in progress transition between reception and transmission. With reference to figure 1, and to a preferred embodiment of the invention, 100 indicates a portable transceiver antenna, usable for satellite or terrestrial radio communications, incorporating a self-powered amplifier device 1 object of the invention. In particular, the antenna 100 comprises a body 100a, adapted to support the functional components of the antenna 100 itself, and to act simultaneously from the handle to allow its use in the field by a subject who needs to carry out radio communications, for example a soldier during an operational action. It is to be understood that both the antenna typology 100 illustrated, as well as its methods of use, are described and illustrated for the purely for illustrative purposes. The self-powered amplifier device 1 item of the invention, in fact, can be advantageously installed on any transceiver antenna in which the presence of an amplifier is foreseen low noise for the receiving signal. In more detail, the antenna 100 comprises a radiating assembly 101, supported at one end of the body 100a, which in the example illustrated is of the type with crossed dipoles. The device is electrically connected to the radiant group 101 self-powered amplifier 1, basically built on a circuit board printed installed inside the same body 100a, which is also connected, by means of a signal line 104, to a terminal of input / output 102. The latter is fixed to the opposite end of the body 100a with respect to the radiant group 101, and is intended to allow connection to a radio equipment 103, transmitting and receiving, via a line of connection 105. The radio equipment 103 is of a known type, and provides for making available on connection line 105, only during reception phases, a direct current power source. Figure 2 shows the amplifier device 1, in a reception phase. of the radio frequency (RF) signal, in which the radiating group 101 is excited by an electromagnetic field and produces a low-frequency RF signal power, intended to be amplified before being forwarded to the radio equipment 103 via the input / output terminal 102 and the connecting line 105. In this regard the amplifier device 1 comprises a RF 2 low noise amplifier (LNA – Low Noise Amplifier), a first electronic switching device 3 and a second switching device electronic 4, the latter intended to insert the LNA 2 in circuit between the group radiating 101 and the input / output terminal 102 during the receiving phases, and to exclude it during the transmission phases. All the devices listed above are of a substantially known type, and will therefore not be described with more detail. In particular, during the reception phases, an IN input of LNA 2 is electrically connected to the radiating group 101 with the interposition of the first switch 3; an output OUT of the same LNA 2 is connected to the line signal 104 and, through this, to the input / output terminal 102. Figure 3 illustrates a schematic of an antenna 100 in transmission mode. In in this case the output RF signal is routed by the first 3 switches and second 4 towards a bypass line LB, excluding from the circuit the LNA 2, whose connections are shown in dotted lines as they are not active. In the diagram figure 2 the aforementioned bypass line LB is illustrated in dashed lines, as the itself is not used in the receiving phase. This way, RF signal paths are established between the group radian 101 and input / output connector 102 comprising the LNA 2 during the reception phases, and which exclude it during the transmission phases. In these phases the LNA 2 is not powered, since the radio 103 does not provide plus the direct current on signal line 104. During the RF signal reception phases the necessary power supply is direct current to LNA 2 and to the first 3 and second 4 switches is supplied on signal line 104 from radio 103. The power required to operation of LNA 2 and switches 3,4 is taken from circuits of completely known power supply. According to the invention, the self-powered amplifier device 1 It also includes auxiliary power supplies 5 of the aforementioned first switches 3 and second 4 (see figures 2 and 3), active during the transmission phases of RF signal and intended to provide electrical power to switches 3,4 during these phases, since they, like the LNA 2 on the other hand, can no longer be powered by radio 103. In this regard, In particular, the auxiliary power supplies 5 comprise a converter RF / DC (Radio Frequency to Direct Current) 51, connected to the power line signal 104 and capable of taking a portion of this signal, which is not significant compared to the power of the RF signal present on the line, to convert it into direct current at the nominal supply voltage of the switches first 3 and second 4. The RF / DC converter 51 is therefore only active during the phases of transmission, when there is a high power RF signal on the line, and can be achieved, in practice, according to one of the various techniques of AC / DC conversion notes for the average experienced technician. In particular, it includes an RF signal rectifier, intended to rectify the signal current and transform it into direct current, at a voltage between 3 and 5.5 VDc, necessary to ensure correct switching devices 3,4. The rectifier circuitry is chosen from configurations known to the designer of average experience, and it is appropriate sized to draw only the power strictly necessary to power the switches 3,4. The converter 51 also includes a section stabilizer, to provide them with their nominal supply voltage. The output of the RF / DC converter 51 is connected to the inputs of power supply of the aforementioned switches 3,4 by means of an “OR” device with very low drop-out, also of a type known to the designer, to the circuit continuous withdrawal from the line during the receiving phase normally foreseen for such components, with the aid of suitable means designed to allow, both power supply via the DC supplied by the 103 radio during reception, both that supplied by converter 51 during transmission. To improve understanding of the feeding pathways of switches 3,4 in the different operating phases of the antenna 100, in figure 3 is the power supply line coming out of the converter is shown in solid lines RF / DC 51, active during transmission, while in figure 2 this line is represented in dashed lines as it is not active. It is considered appropriate to point out that the switches 3,4, which have been up to now identified, in the text and figures, as distinct and separate components, at a construction level they can also be found assembled in a single device, usually expressly designed to perform the functions of components an LNA, as they have been described so far. It is understood that, from a point of view from a purely functional point of view, even in this case the two components operate independently of each other. In order to ensure the necessary power supply of the switches 3,4 even during the transition phase of switching the radio 103 between the phase of reception and transmission, the power supply means 5 also provide (see figure 4) an energy storage device 52, connected to the line of RF signal 104 and to the first 3 and second 4 switches, intended for accumulate energy during the reception phases, and maintain the power supply to the same in the very short transition periods between the reception and release phases transmission. The above mentioned energy storage device 52 comprises preferably a capacitor 53, connected to the RF signal line 104, in “OR” configuration with the aforementioned RF / DC converter 51, and with the interposition of insulating means 54; the latter are made up of a high frequency impedance, and are intended to take up part of the continuous component present on the RF signal line 104 during the phases of reception, to charge the capacitor 53 and thus make available a electric charge when, at the moment in which the radio 103 stops providing the continuous component at the end of a reception phase, the above mentioned RF / DC converter 51 cannot yet supply auxiliary power to the switches 3,4. This prevents the switches 3,4 from remaining for a few moments without power, and thus any risk is avoided that the themselves keep the LNA 2 in circuit for a moment longer when on the line of signal 104 the RF power signal is provided for transmission, situation that could seriously damage the LNA 2 itself. Again, for clarity, the power lines of the switches 3,4 coming from the energy storage device 52 are represented in figure 4 with solid lines as they are active during the transitory, while in figures 2 and 3 they are represented in dashed lines since they are not active. It is understood that different solutions for the battery storage device energy 52 can be adopted without departing from the purposes of the invention. From the above it is clear that the amplifying device self-powered 1 allows you to use, in an antenna equipped with amplification of the receiving signal using LNAs, electronic switches with very high switching speed, low noise and long life and reliability, even in RF transceiver equipment in which the radio provides a continuous component in line only during the reception phases of the RF signal. However, it is understood that the above description has an exemplary value. and not limiting; therefore, any variations in detail that may arise necessary for technical and / or functional reasons, are considered from now on falling within the same protective scope defined by the following

Claims

1. Self-powered amplifier device for a transceiver antenna, said antenna (100) comprising a radiating assembly (101) capable of transmitting and receiving radio frequency (RF) signals in the form of radio waves, and an input / output terminal (102) capable of allowing the connection of said antenna (100) to a radio equipment (103), said self-powered amplifier device (1) being characterised in that it comprises: - a low noise RF amplifier (2), capable of amplifying an RF signal injected into its own input (IN) and making it available at its own output (OUT); - a first electronic switching device (3), electrically connected to said radiating assembly (101), to said input (IN) of the RF amplifier (2) and to a bypass signal line (LB);- a second electronic switching device (4), electrically connected to said terminal (102) by means of a signal line (104) internal to said antenna (100), to said output (OUT) of the RF amplifier (2) and to said bypass signal line (LB); - said first (3) and second (4) electronic switching devices being provided to define signal connections between said terminal (102) and radiating group (101) to include said RF amplifier (2) during the signal reception phases, and to exclude it during the transmission phases, by diverting the transmitted signal towards the aforementioned bypass signal line (LB);- power supply means (5) of said first (3) and second (4) electronic switching devices, comprising an RF / DC converter (51) connected to said signal line (104), suitable for taking from the same a part of the RF power signal during the transmission phases and converting it into direct current, and also connected to said first (3) and second (4) electronic switching devices to supply them with electrical power during the aforementioned transmission phases.; 2. Amplifying device according to claim 1, characterised in that said power supply means (5) further comprise an energy accumulator device (52), connected to said signal line (104) and to said first (3) and second (4) switching devices, intended to accumulate energy during said reception phases and contribute to powering said first (3) and second (4) switching devices during the transition periods between reception and transmission.

3. Amplifier device according to claim 1, characterized in that said RF / DC converter (51) comprises a high frequency rectifier sized to rectify part of the current of said RF power signal and transform it into direct current, at a voltage between 3 and 5.5 VDC.

4. Amplifier device according to claim 2, characterised in that said energy accumulator device (52) comprises at least one capacitor (53), connected in “OR” configuration to the aforementioned RF / DC converter (51).

5. Amplifying device according to claim 4, characterised in that said energy accumulator device (52) further comprises insulating means (54), interposed between said capacitor (53) and said signal line (104), suitable for taking the direct component from the latter to charge the aforementioned capacitor (53).

6. Amplifying device according to claim 5, characterised in that, in said first (3) and second (4) switching devices, the transition between the power supply of the same during the reception and transmission phases occurs by means of the supply of energy by the aforementioned capacitor (53)