DESC:FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

Title: DUAL CHANNEL SOLID STATE POWER AMPLIFIER WITH MULTI-MODE AND MULTI-CARRIER OPERATION

APPLICANT DETAILS:
(a) NAME: BHARAT ELECTRONICS LIMITED
(b) NATIONALITY: Indian
(c) ADDRESS: OUTER RING ROAD, NAGAVARA, BANGALORE -560045,
KARNATAKA,INDIA

PREAMBLE TO THE DESCRIPTION:
The following specification (particularly) describes the nature of the invention (and the manner in which it is to be performed):

DUAL CHANNEL SOLID STATE POWER AMPLIFIER WITH MULTI-MODE AND MULTI-CARRIER OPERATION

FIELD OF INVENTION:
The present disclosure relates to a Dual Channel Solid State Power Amplifier (SSPA) for aerospace applications, supporting multi-mode operation and efficient amplification of various digital modulations while ensuring compactness, lightweight, and thermal management.

BACKGROUND OF THE INVENTION:
The following background discussion includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication expressly or implicitly
The progresses in semiconductor technology demand compact high-power Solid-State Power Amplifier (SSPA) for wireless Military Communications and also to have reliable communication. SSPAs need to support amplification of various digital modulations which demand linear operation. Dual channel SSPAs with two input ports and single output port have a means of combining the final amplified power from RF channel 2 into the higher power RF channel 1 using coupler to radiate amplified signal from a single Antenna. The radiated signal consists of information amplified by both the channels operating simultaneously at different frequencies. To support amplification of higher order digital modulations the SSPA needs to operate in linear region and to achieve better battery usage the SSPA should be efficient and for airborne application it should be compact and light weight.
CN112332782A [2020] Broadband C-band solid-state power amplifier module discloses a broadband C-band solid-state power amplifier module which comprises a C-band solid-state power amplifier assembly, a heat dissipation system and apower amplifier fixing device. SSPA adopted modular design. A feed and protection circuit is used for supplying power and protecting a power amplifier. The micro rectangular connector is used for supplying power to the feeding and protecting circuit and generating interactive information with an external system. Further, the C-band radio frequency amplification link comprises an input isolator, a front-stage GaAs power amplifier, a final-stage GaN power amplifier and an output isolator which are sequentially connected.
US10637519B2 [2020] Dual Band Amplifier, discloses a concurrent-type multiband amplifier (or a dual-band amplifier) which amplifies multiband signals concurrently using a plurality of (N ) amplifier circuits which each independently amplify signals in a plurality of (N ) frequency bands. An n -th (n = any of 1 to N ) amplifier circuit is provided with a circuit for blocking signals in frequency bands other than the n -th frequency band so as to amplify and output only the n -th frequency band signal.
US7605651B2 [2012] Multimode Amplifier for Operation in Linear and Saturated modes: A multimode power amplifier configured to receive an RF input signal and provide an RF output signal in linear and saturated operating modes includes an output stage configured to receive a fixed supply voltage and to provide the RF output signal. The multimode power amplifier further includes at least one driver stage coupled to the output stage, where the at least one driver stage is configured to receive the RF input signal and an adjustable Supply Voltage. The adjustable Supply Voltage controls an RF output power of the RF output signal when the multimode power amplifier is in the Saturated operating mode. The at least one driver and the output stage are each biased by a low impedance Voltage in the linear and Saturated operating modes. The adjustable Supply Voltage can be controlled by a fixed control Voltage in the linear operating mode.
IEEE 2020: Integrated Microfluidic Cooling for S-Band 10-Watt
CW Power Amplifiers on Hybrid PCBs: presents an integrated microfluidic channel on a Rogers and FR4 hybrid printed circuit board (PCB) to cool an S-band 10 W CW (continuous-wave) power amplifier in a plastic surface mount package. A four-layer hybrid PCB has been designed and fabricated, whose fabrication process is completely based on the standard multilayer PCB technology.

OBJECTIVES OF THE INVENTION:
The primary object of the present invention is to overcome the problem stated in the prior art.
Another object of the present invention provides a Dual Channel Solid State Power Amplifier (SSPA) for aerospace applications, supporting multi-mode operation and efficient amplification of various digital modulations while ensuring compactness, lightweight, and thermal management.

SUMMARY OF THE INVENTION:
The present invention provides a dual channel solid state power amplifier comprising:
a) a RF Channel-1(100), a RF Channel-2(121) and a directional coupler (123) to combine both channel’s amplified signal, where the RF Channel-1 consists of an isolator(101) as its first input component to improve input standing wave, followed by a limiter(102) to prevent damage to the MMICs due to excessive power at the input of the system;
b) an integrated low pass filter (124), power supply distribution, Monitor and a control circuit (122),
c) a heat dissipation system (202) including avionics grade fans (200,201); and
d) a power amplifier assembly (203) wherein dual channel SSPA relates to the heat dissipation system.
In an embodiment, the voltage variable attenuator (103) is configured to control gain and to maintain constant output power in association with gain control circuit.
In an embodiment, the voltage variable attenuator(103) is followed by a GaAs based low power pre-driver gain stage(104), GaAs based internally matched a multi stage high gain driver device(105), a 90° hybrid splitter(106) to equally split the input signal with a 90° phase shift between ports and if any reflection from mismatches at the output port flow towards isolated port.
In an embodiment, the output isolators(109,110) after final amplifier stage is configured for protection against reverse power during accidental open condition of the output connector, followed by 90° hybrid combiner(111) to combine two signals equally into single signal, then signal is made to pass through directional coupler(112) to get samples of forward and reflected power.
In an embodiment, the RF Channel-2(121) consists of an isolator(113) as its first input component to improve input standing wave, followed by a limiter(114) to prevent damage to the MMICs due to excessive power at the input of the system, then a voltage variable attenuator(115) to control gain and to maintain constant output power in associated with gain control circuit, followed by GaAs based low power pre-driver gain stage(116), a GaAs based internally matched multi stage high gain driver device(117).
In an embodiment, the GaN based final amplification stage (118), an output isolator (119) after final amplifier stage is used for protection against reverse power, output from isolator (119) is made to pass through directional coupler (120) to get samples of forward and reflected power.
In an embodiment, the low loss directional coupler (123) is configured to combine final amplified power from Channel-2(121) into the other higher power Channel-1(100) before the output port to radiate amplified signal from a single Antenna for further transmission.
In an embodiment, the combined signals are made to pass through integrated low pass filter (124) to reject harmonics components from the output signal.
In an embodiment, the power supply and digital block(122) comprises of power supply distribution circuit, separate power supply sequence circuits of gate and drain supply sequencing for GaN based amplifiers, a microcontroller based monitor and control circuit to provide protection against High temperature, High output VSWR, Input Over drive and Input over-voltage.
The present invention provides a method of operation of the dual channel solid state power amplifier as claimed in claim 1, comprising steps of:
a) enabling usage of only one channel or both channels to amplify two different modulations simultaneously and to operate the channels with division in time or frequency or both; and
b) providing a separate gain control circuit for each path and enabling the coupler for combining the final amplified power from RF channel 2 into higher power RF channel 1 before the output port to radiate amplified signal from a single Antenna.

DETAILED DESCRIPTION OF DRAWINGS:
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of their scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings in which:
Fig. 1: illustrates the RF Block diagram of Solid-State Power Amplifier.
Fig. 2: illustrates fabricated model of Module assembly of SSPA.

DETAILED DESCRIPTION:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
The terms “comprises”, “comprising”, “includes”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
The present invention relates to Dual Channel Solid State Power Amplifier with multi-mode operation. Amplifying concurrent signals allows for increased data through put. This SSPA supports amplification of various digital modulations which demand linear operation.
The present disclosure provides for a method of reducing hardware complexity. Present disclosure also provides for a method that enables usage of only one channel or both channels to amplify two different modulations simultaneously and to operate the channels with division in time or frequency or both. Present disclosure provides a separate gain control circuit for each path. Present disclosure provides a method that enables the use of coupler for combining the final amplified power from RF channel 2 into higher power RF channel 1 before the output port to radiate amplified signal from a single Antenna.
In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows: The system comprises of RF Channel-1(100), RF Channel-2(121), a directional coupler (123) to combine both channel’s amplified signal, Integrated low pass filter(124), power supply distribution, Monitor and control circuit(122), heat dissipation system(202) including avionics grade fans (200,201) and power amplifier assembly(203) wherein dual channel SSPA is connected with the heat dissipation system.
The present invention provides a dual channel solid state power amplifier comprising:
a) a RF Channel-1(100), a RF Channel-2(121) and a directional coupler (123) to combine both channel’s amplified signal, where the RF Channel-1 consists of an isolator(101) as its first input component to improve input standing wave, followed by a limiter(102) to prevent damage to the MMICs due to excessive power at the input of the system;
b) an integrated low pass filter (124), power supply distribution, Monitor and a control circuit (122),
c) a heat dissipation system (202) including avionics grade fans (200,201); and
d) a power amplifier assembly (203) wherein dual channel SSPA relates to the heat dissipation system.
In an embodiment, the voltage variable attenuator (103) is configured to control gain and to maintain constant output power in association with gain control circuit.
In an embodiment, the voltage variable attenuator(103) is followed by a GaAs based low power pre-driver gain stage(104), GaAs based internally matched a multi stage high gain driver device(105), a 90° hybrid splitter(106) to equally split the input signal with a 90° phase shift between ports and if any reflection from mismatches at the output port flow towards isolated port.
In an embodiment, the output isolators (109,110) after final amplifier stage is configured for protection against reverse power during accidental open condition of the output connector, followed by 90°hybrid combiner (111) to combine two signals equally into single signal, then signal is made to pass through directional coupler (112) to get samples of forward and reflected power.
In an embodiment, the RF Channel-2(121) consists of an isolator(113) as its first input component to improve input standing wave, followed by a limiter(114) to prevent damage to the MMICs due to excessive power at the input of the system, then a voltage variable attenuator(115) to control gain and to maintain constant output power in associated with gain control circuit, followed by GaAs based low power pre-driver gain stage(116), a GaAs based internally matched multi stage high gain driver device(117).
In an embodiment, the GaN based final amplification stage (118), an output isolator (119) after final amplifier stage is used for protection against reverse power, output from isolator (119) is made to pass through directional coupler (120) to get samples of forward and reflected power.
In an embodiment, the low loss directional coupler (123) is configured to combine final amplified power from Channel-2(121) into the other higher power Channel-1(100) before the output port to radiate amplified signal from a single Antenna for further transmission.
In an embodiment, the combined signals are made to pass through integrated low pass filter (124) to reject harmonics components from the output signal.
In an embodiment, the power supply and digital block (122) comprises of power supply distribution circuit, separate power supply sequence circuits of gate and drain supply sequencing for GaN based amplifiers, a microcontroller based monitor and control circuit to provide protection against High temperature, High output VSWR, Input Over drive and Input over-voltage.
The present invention provides a method of operation of the dual channel solid state power amplifier as claimed in claim 1, comprising steps of:
a) enabling usage of only one channel or both channels to amplify two different modulations simultaneously and to operate the channels with division in time or frequency or both; and
b) providing a separate gain control circuit for each path and enabling the coupler for combining the final amplified power from RF channel 2 into higher power RF channel 1 before the output port to radiate amplified signal from a single Antenna.
RF Channel-1 consists of an isolator(101) as its first input component to improve input standing wave, followed by a limiter(102) to prevent damage to the MMICs due to excessive power at the input of the system, then a voltage variable attenuator(103) to control gain and to maintain constant output power in association with gain control circuit. voltage variable attenuator(103) is followed by GaAs based low power pre-driver gain stage(104), GaAs based internally matched multi stage high gain driver device(105), a 90° hybrid splitter(106) to equally split the input signal with a 90°phase shift between ports and if any reflection from mismatches at the output port flow towards isolated port, followed by GaN based final amplification stage(107,108) which is achieved by parallel cascading, an output isolators(109,110) after final amplifier stage is used for protection against reverse power during accidental open condition of the output connector, followed by 90° hybrid combiner(111) to combine two signals equally into single signal, then signal is made to pass through directional coupler(112) to get samples of forward and reflected power. R1 and R2 are 50-ohm terminations.
RF Channel-2(121) consists of an isolator(113) as its first input component to improve input standing wave, followed by a limiter(114) to prevent damage to the MMICs due to excessive power at the input of the system, then a voltage variable attenuator(115) to control gain and to maintain constant output power in associated with gain control circuit, followed by GaAs based low power pre-driver gain stage(116), a GaAs based internally matched multi stage high gain driver device(117), a GaN based final amplification stage(118), an output isolator(119) after final amplifier stage is used for protection against reverse power, output from isolator(119) is made to pass through directional coupler(120) to get samples of forward and reflected power.
Furthermore, low loss directional coupler (123) is used to combine final amplified power from Channel-2(121) into the other higher power Channel-1(100) before the output port to radiate amplified signal from a single Antenna for further transmission.
R3 is 50-ohm terminations. Combined signals are made to pass through integrated low pass filter (124) to reject harmonics components from the output signal.
Furthermore, power supply and digital block(122) comprises of power supply distribution circuit, separate power supply sequence circuits of gate and drain supply sequencing for GaN based amplifiers, a microcontroller based monitor and control circuit to provide protection against High temperature, High output VSWR, Input Over drive and Input over-voltage.
The complete SSPA is constructed out of a single piece Aluminum milled block with individual pockets, shielding each stage from the next stage to prevent mutual interference. Thermal management of the heat generated is accomplished using heat sink and two avionics grade cooling fans. While the first fan is switched ON automatically at Power ON condition, the second fan is energized only on failure of the first fan or on temperature exceeding the pre-defined threshold value. Fan operational / failure status is indicated using the communication port.
A full-duplex asynchronous communication protocol is employed to communicate between this SSPA module and external modules. All configuration controls like soft shutdown & power mode selection and health monitoring’s like forward and reflected power of both the channels, temperature, status of cooling fans, input over-voltage are carried out using this communication protocol.
Furthermore, this SSPA module employs a single multilayer Hybrid PCB to integrate power supply circuit, digital circuits and RF circuits in one PCB. A 10-layer Hybrid PCB is used with top layer made up of high frequency PTFE dielectric material, while the dielectric material of other layers is chosen to be FR4. Hybrid PCB helps in reducing overall electronics packaging size, elimination of interconnection cables, better integrated EMI shielding, improved reliability and reduced cost.
Furthermore, to improve the reliability and provide graceful degradation of RF Channel-1 path(100), parallel cascading of final power stage is employed. This ensures that in the event of failure of any one of the last power stage, the unit continues to function, though with reduced power output. A programmable attenuator allows the RF Channel-1 power output to be programmed for High Power (HP) or Low Power (LP) mode, based on external control logic through the RS-422 port.
It is imperative to emphasize that this embodiment serves as an illustrative example and does not impose constraints on the overall scope of the present invention. All modifications, refinements, improvements, or adaptations made within the permissible bounds of this patent are explicitly included and recognized. Thus, any changes or progressions implemented in the disclosed embodiment, as long as they stay within the defined parameters of the patent, are regarded as essential components of and shielded by this invention.
The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.

,CLAIMS:We Claim:

1. A dual channel solid state power amplifier comprising:
a) a RF Channel-1(100), a RF Channel-2(121) and a directional coupler (123) to combine both channel’s amplified signal, where the RF Channel-1 consists of an isolator(101) as its first input component to improve input standing wave, followed by a limiter(102) to prevent damage to the MMICs due to excessive power at the input of the system;
b) an integrated low pass filter (124), power supply distribution, Monitor and a control circuit (122),
c) a heat dissipation system (202) including avionics grade fans (200,201); and
d) a power amplifier assembly (203) wherein dual channel SSPA is connected with the heat dissipation system.
2. The dual channel solid state power amplifier as claimed in claim 1, wherein a voltage variable attenuator (103) is configured to control gain and to maintain constant output power in association with gain control circuit.
3. The dual channel solid state power amplifier as claimed in claim 1, wherein the voltage variable attenuator(103) is followed by a GaAs based low power pre-driver gain stage(104), GaAs based internally matched a multi stage high gain driver device(105), a 90° hybrid splitter(106) to equally split the input signal with a 90° phase shift between ports and if any reflection from mismatches at the output port flow towards isolated port.
4. The dual channel solid state power amplifier as claimed in claim 1, wherein an output isolators(109,110) after final amplifier stage is configured for protection against reverse power during accidental open condition of the output connector, followed by 90° hybrid combiner(111) to combine two signals equally into single signal, then signal is made to pass through directional coupler(112) to get samples of forward and reflected power.
5. The dual channel solid state power amplifier as claimed in claim 1, wherein the RF Channel-2(121) consists of an isolator(113) as its first input component to improve input standing wave, followed by a limiter(114) to prevent damage to the MMICs due to excessive power at the input of the system, then a voltage variable attenuator(115) to control gain and to maintain constant output power in associated with gain control circuit, followed by GaAs based low power pre-driver gain stage(116), a GaAs based internally matched multi stage high gain driver device(117).
6. The dual channel solid state power amplifier as claimed in claim 1, wherein a GaN based final amplification stage (118), an output isolator (119) after final amplifier stage is used for protection against reverse power, output from isolator (119) is made to pass through directional coupler (120) to get samples of forward and reflected power.
7. The dual channel solid state power amplifier as claimed in claim 1, wherein the low loss directional coupler (123) is configured to combine final amplified power from Channel-2(121) into the other higher power Channel-1(100) before the output port to radiate amplified signal from a single Antenna for further transmission.
8. The dual channel solid state power amplifier as claimed in claim 1, wherein the combined signals are made to pass through integrated low pass filter (124) to reject harmonics components from the output signal.
9. The dual channel solid state power amplifier as claimed in claim 1, wherein the power supply and digital block(122) comprises of power supply distribution circuit, separate power supply sequence circuits of gate and drain supply sequencing for GaN based amplifiers, a microcontroller based monitor and control circuit to provide protection against High temperature, High output VSWR, Input Over drive and Input over-voltage.
10. A method of operation of the dual channel solid state power amplifier as claimed in claim 1, comprising steps of:
a) enabling usage of only one channel or both channels to amplify two different modulations simultaneously and to operate the channels with division in time or frequency or both; and
b) providing a separate gain control circuit for each path and enabling the coupler for combining the final amplified power from RF channel 2 into higher power RF channel 1 before the output port to radiate amplified signal from a single Antenna.