Amplification apparatus

The present invention relates to a signal amplification technique for amplifying radio frequency (RF) signals.

In recent years, there has been an increased expectation of demand for amplification apparatuses which have a solid state power amplifier (SSPA) for providing amplification capability of RF signals, and which may be used in place of magnetron oscillators having a magnetron, which is a widely used oscillator/amplifier element. A typical existing magnetron oscillator is constructed as an apparatus having no onboard power supply unit and being adapted for connection with a separate power supply apparatus through a power supply cable, through which power having a high voltage is supplied to the magnetron oscillator. Under the circumstances, it is desirable that an SSPA based amplification apparatus, which is intended to be used in place of an existing magnetron oscillator, may be constructed as an apparatus which is supplied with power from a separate power supply apparatus.

As a related technique, a semiconductor power amplifier system for powering an element of an antenna is known from Patent Document No. 1 listed below (Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-536483). The semiconductor power amplifier system includes: an RF amplifier means, having a power output stage; a power supply means for providing a variable value of DC voltage for powering the power output stage; and a control means for receiving as a control input an input power signal of the RF amplifier means, for providing, in response to the control input, a voltage control signal to the power supply means to determine the value of the DC voltage.

Patent Document(s)

Patent Document No. 1: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-536483

Problems to be Solved by the Invention

Unfortunately, a typical operational voltage for magnetrons is as high as about 5 kilovolts, while that for SSPA based amplification apparatuses is as low as about 30 volts. Thus, if the power level of the supplied power to an SSPA based amplification apparatus is alike to that to a magnetron oscillator, the supplied power to the former should have a far lower voltage and a far higher current than that to the latter. This means that the power supply cable for connecting an SSPA based amplification apparatus with a separate power supply apparatus needs to be extremely thick and/or the length of the power supply cable needs to be so limited, which could be substantial restrictions preventing the practical realization of SSPA based amplification apparatuses, and could raise a problem of difficulty in supplying an SSPA based amplification apparatuses with power from a separate power supply apparatus.

The present invention is achieved in order to solve the above mentioned problem. Accordingly, it is an object of the present invention to provide an amplification apparatus, which may be supplied with power from a separate power supply apparatus with more ease.

Resolution

In order to achieve the above object, an amplification apparatus according to the present invention comprises: at least one voltage converter for converting a voltage of supplied power which is supplied from an external power supply source to the amplification apparatus, to a lower voltage; and at least one amplifier unit operable by supplied power which has the lower voltage as converted by the at least one voltage converter, for amplifying a radio frequency signal.

Advantages Provided by the Invention

According to the present invention, there is advantageously provided an amplification apparatus, which may be supplied with power from a separate power supply apparatus with more ease.

FIG. 1 is a schematic perspective view of an amplification apparatus according to an embodiment of the present invention with a separate power supply apparatus.

FIG. 2 is a high level block diagram of the amplification apparatus.

FIG. 3 is a block diagram of a gain module.

FIG. 4 is a block diagram of an amplifier unit.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

First, an amplification apparatus according to an embodiment of the present invention and a separate power supply apparatus will be described in general. FIG. 1 is a schematic perspective view of the amplification apparatus according to the embodiment of the present invention with the separate power supply apparatus. FIG. 2 is a high level block diagram of the amplification apparatus.

As shown in FIG. 1 , the amplification apparatus 1 is connected with the power supply apparatus 2 by means of a power supply cable 3 , through which the power supply apparatus 2 supplies the amplification apparatus 1 with power having a relatively high voltage of about 300 volts. The voltage of the power supplied to the amplification apparatus 1 is converted down to a lower voltage of about 30 volts within the amplification apparatus 1 .

As shown in FIG. 2 , the amplification apparatus 1 includes: i) a gain module 11 for receiving an input RF signal, splitting the received RF signal into a plurality of split RF signals and outputting them; ii) a plurality of amplifier units 12 for receiving the split RF signals, respectively, and amplifying them, respectively; iii) a signal combiner 13 for combining the amplified RF signals, which are amplified by the respective amplifier units 12 , into a combined RF signal and outputting it; and (iv) a hollow waveguide 14 for receiving the combined RF signal outputted from the signal combiner 13 .

Next, the structures of the gain module and the amplifier unit will be described. FIG. 3 is a block diagram of the gain module. FIG. 4 is a block diagram of the amplifier unit.

As shown in FIG. 3 , the gain module 11 includes an input power monitor 110 , an RF switch 111 , a variable attenuator 112 , a fixed attenuator 113 , an amplifier 114 , a signal splitter 115 , a plurality of adjustments 116 , and a voltage converter 119 .

The input power monitor 110 determines whether or not the power level of an input RF signal received from an external source is appropriate and, if so, outputs the received RF signal to the RF switch 111 . The RF switch 111 may be set either “ON” or “OFF” depending on an external control. The RF switch 111 then outputs the received RF signal to the variable attenuator 112 only when it is set “ON”. The variable attenuator 112 , the attenuation level of which is variable and adjustable, reduces the power level of the received RF signal based on an externally supplied control signal, and outputs the resulting attenuated RF signal to the fixed attenuator 113 . The fixed attenuator 113 , the attenuation level of which is fixed, reduces the power level of the received RF signal and outputs the resulting attenuated RF signal to the amplifier 114 . The amplifier 114 amplifies the received RF signal and outputs the resulting amplified RF signal to the signal splitter 115 . The signal splitter 115 splits the received FR signal into a plurality of RF signals and outputs them to the plurality of adjustments 116 , respectively.

Each adjustment 116 includes an amplitude/phase adjuster 117 and a pre-driver amplifier 118 . Each adjustment 116 serves to adjust the amplitude and the phase of the received RF signal, which is outputted from the signal splitter 115 , and further serves to output the resulting adjusted RF signal to the associated one of the amplifier units 12 . The amplitude/phase adjuster 117 , which may include, for example, a variable attenuator and a phase shifter, adjusts the amplitude and the phase of the received RF signal and outputs the resulting adjusted RF signal to the pre-driver amplifier 118 . The pre-driver amplifier 118 amplifies the received RF signal and outputs the resulting amplified RF signal to the associated one of the amplifier units 12 . The adjustment levels of the amplitude adjustment and the phase adjustment are settable for each adjustment 116 independently from other adjustments 116 , and the setting of the adjustment levels for all the adjustments 116 is achieved, for example, before shipment of the amplification apparatus 1 , such that all the RF signals to be outputted from the respective adjustments 116 may have a substantially equal amplitude and may be substantially in phase with one another.

The voltage converter 119 is a DC-to-DC converter serving to convert the voltage of the power, which is supplied from the power supply apparatus 2 through the power supply cable 3 , from 300 volts down to 30 volts. The voltage converter 119 further serves to superimpose the resulting DC voltage of 30 volts onto the respective RF signals which are outputted from the adjustments 116 to the associated amplifier units 12 .

As shown in FIG. 4 , each amplifier unit 12 includes a driver amplifier 120 and a final amplifier 121 , each formed as a semiconductor device, and a voltage converter 122 . The driver amplifier 120 amplifies the RF signal inputted to and received by the amplifier unit 12 and outputs the resulting amplified RF signal to the final amplifier 121 . The final amplifier 121 amplifies the received RF signal, which is outputted from the driver amplifier 120 , and outputs the resulting amplified RF signal to the signal combiner 13 . The voltage converter 122 , like the above mentioned voltage converter 119 , is a DC-to-DC converter serving to convert the voltage of the power, which is supplied from the power supply apparatus 2 through the power supply cable 3 , from 300 volts down to 30 volts. The voltage converter 122 supplies power having the converted voltage of 30 volts to the driver amplifier 120 and the final amplifier 121 . The RF signals outputted from the amplifier units 12 are combined together by the signal combiner 13 and the resulting combined RF signal is outputted to the hollow waveguide 14 .

As mentioned above, the power supply apparatus 2 supplies the amplification apparatus 1 with power having a relatively high voltage of about 300 volts and a relatively low current, and the voltage of the supplied power is converted down to a lower voltage of about 30 volts within the amplification apparatus 1 , so that the amplification apparatus 1 may be supplied with power from the separate power supply apparatus 2 through the power supply cable 3 , which does not need to be so thick nor so short. By virtue of this, an SSPA based amplification apparatus may be constructed with only a little modification to an existing magnetron oscillator, that is, an SSPA may be used with more ease in place of a magnetron.

The above described embodiment of the present invention is for illustrative purpose only and is not intended to limit the scope of the invention. The novel embodiment may be embodied in various other forms, and may be subject to various abbreviations, substitutions and alterations without departing from the spirit of the invention. The above described embodiment and any possible modifications thereof are encompassed within the scope and spirit of the invention, as well as within the scope of the claimed invention and of any equivalents thereof.

1 Amplification apparatus

12 Amplifier unit

13 Signal combiner

115 Signal splitter

119 Voltage converter

122 Voltage converter