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

Title: A WIDE BAND HIGH POWER AMPLIFIER

APPLICANT DETAILS:
(a) NAME: BHARAT ELECTRONICS LIMITED
(b) NATIONALITY: Indian
(c) ADDRESS: Outer Ring Road, Nagavara, Bangalore - 560045

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

A WIDE BAND HIGH POWER AMPLIFIER

FIELD OF INVENTION:
The present disclosure/invention generally relates to power amplifier and more particularly to a wide band high power amplifier.

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
Generally, power amplifiers are one of the major components of Transmit/Receive modules which are targeted for efficiency improvement due to large output power generated. T/R modules with highly integrated devices enable beam-forming and steering, form the heart of Active Phase Array Radars. Size, weight and power (Swap) are the key criteria in these RADAR and communication platforms.
Output power and bandwidth are two parameters to be traded-off in the design of conventional power amplifiers. The reason for such compromise is due to the fact that, a conventional power amplifier is normally comprised of many active devices combined in parallel to achieve the required power level. When many active devices are combined in parallel, the collective impedance decreases drastically. Subsequently, this combined and reduced impedance must be transformed back to the 50-Ohm system using an elaborate, often in the form of a multi-section topology, circuit which is either narrow band or large in size or both. Thus, conventional power amplifier designs often yield limited bandwidth.
One of the prior art discloses 2W GaN MMIC Power amplifier operates in the frequency range of 2.7-3.5GHz.
Further prior art discloses RF Power amplifier with frequency selective impedance matching network.
Further prior art discloses 4.0-5.0GHz 8W GaN MMIC power amplifier and design method.
Another prior art discloses single stage broadband power amplifier circuits with high efficiency over a broad bandwidth.
Another prior art discloses “Compact 20-W GaN Internally Matched Power Amplifier for 2.5 GHz to 6GHz Jammer Systems” claims linear gain of about 10.2 dB and had an output power of 43.3–43.9 dBm (21.4–24.5 W), a power-added efficiency of 33.4–49.7% and a power gain o6.2–8.3 dB at the continuous-wave output power condition, from 2.5 to 6 GHz. However, it provides less large signal gain, hence more input is required to achieve saturated output power.
However, the above-mentioned prior art amplifier architectures fall far short of realizing an amplifier architecture that can simultaneously achieve both high output power and extremely wide bandwidth in the form of MMIC (Microwave Monolithic Integrated Circuit).
Therefore, there is a need in the art with a wide band high power amplifier to solve the above-mentioned limitations.

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 is to provide an amplifier architecture that can simultaneously achieve both high output power and extremely wide bandwidth in the form of MMIC (Microwave Monolithic Integrated Circuit).

SUMMARY OF THE INVENTION:
The present invention provides a wide band high power amplifier comprising:
a) a two-stage wideband MMIC GaN Power amplifier consisting of an input matching network (311), an intermediate matching network (312), an output matching network (313) configured to perform impedance matching of the amplifier; and
b) a FETs in driver (309) and output stage (310) fabricated on 0.25 um GaN HEMT process and packaged in Ceramic/Metal Flange package;
wherein the driver stage and the Power stage have the parallel R-C stability circuit (301,302) to ensure unconditional stability across the wide frequency range.
In an embodiment, an on chip and off chip decoupling capacitors (303, 304, 305, 306) is configured to prevent low frequency oscillations.
In an embodiment, the power amplifier comprises a matching network of input (311), intermediate (312) and output (313) by using reactive matching topology to provide wide bandwidth.
In an embodiment, the power amplifier is biased from dedicated pins, (Vg and Vd).
In an embodiment, an external alumina substrate (200) consists of an inductor (201) connected between D1 and D2 to provide DC-RF isolation and a resistor (202) connected between G1 and G2 to ensure unconditional stability the power amplifier.
In an embodiment, the power amplifier is packaged in 6 pins lead frame format ceramic/metal flange package (100) enabling wide bandwidth to be achieved in a small footprint screw down package featuring a CMC (cu-mo-cu) base heat sink.
In an embodiment, the OFF-Chip comprises spiral inductor and resistor fabricated on 10 mil alumina substrates and integrated in Ceramic/Metal Flange package, where the inductor and the capacitor are mounted on top and bottom to ensure symmetrical operation of the device.

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 a basic architecture of two stage GaN MMIC power amplifier.
Fig. 2: illustrates an application circuit in alumina substrate.
Fig. 3: illustrates MMIC Die of 2 stage GaN Power Amplifier with dimension of 4.5mm x 4.8mm.
Fig. 4: illustrates a RF/DC connection PCB in ceramic substrate.
Fig. 5: illustrates complete packaged MMIC GaN Power amplifier with RF input, RF output, source, drain and gate supply interconnections.

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 various embodiments of the present disclosure/invention describe wideband 30W GaN MMIC High Power Amplifier operated in pulsed conditions for Radar applications.
The present invention provides a wide band high power amplifier comprising:
a) a two-stage wideband MMIC GaN Power amplifier consisting of an input matching network (311), an intermediate matching network (312), an output matching network (313) configured to perform impedance matching of the amplifier; and
b) a FETs in driver (309) and output stage (310) fabricated on 0.25 um GaN HEMT process and packaged in Ceramic/Metal Flange package;
wherein the driver stage and the Power stage have the parallel R-C stability circuit (301,302) to ensure unconditional stability across the wide frequency range.
In an embodiment, an on chip and off chip decoupling capacitors (303, 304, 305, 306) is configured to prevent low frequency oscillations.
In an embodiment, the power amplifier comprises a matching network of input (311), intermediate (312) and output (313) by using reactive matching topology to provide wide bandwidth.
In an embodiment, the power amplifier is biased from dedicated pins, (Vg and Vd).
In an embodiment, an external alumina substrate (200) consists of an inductor (201) connected between D1 and D2 to provide DC-RF isolation and a resistor (202) connected between G1 and G2 to ensure unconditional stability the power amplifier.
In an embodiment, the power amplifier is packaged in 6 pins lead frame format ceramic/metal flange package (100) enabling wide bandwidth to be achieved in a small footprint screw down package featuring a CMC (cu-mo-cu) base heat sink.
In an embodiment, the OFF-Chip comprises spiral inductor and resistor fabricated on 10 mil alumina substrates and integrated in Ceramic/Metal Flange package, where the inductor and the capacitor are mounted on top and bottom to ensure symmetrical operation of the device.
The present invention describes a two stage GaN (Gallium Nitride) HEMT (high-electron-mobility transistor) MMIC (Monolithic Microwave Integrated Circuit) Power Amplifier, which operates between the frequency ranges of S-C band. The amplifier typically provides 25 dB of small signal gain and 30 W saturated output power with an associated power added efficiency of better than 35 %. The wideband amplifier’s input and output are internally matched to 50 Ohm. This amplifier is packaged in at least 6 leads gold plated ceramic/metal flange package, and it can be used in broad band amplifier applications.
In one embodiment, the present invention comprises integration of MMIC power amplifier die with application circuit of RF and DC on alumina substrate packaged in 6 leads ceramic/metal package.
In one embodiment, the present invention provides a novel method of realizing a Wideband 30W GaN MMIC High Power Amplifier operated in pulsed conditions for Radar applications.
In one embodiment, the present invention wide band 30W GaN MMIC High Power Amplifier provides output Power: 30W Typ; power Added Efficiency: 35% Typ; 25dB Small Signal Gain; wide bandwidth and large signal Gain 18dB Typ.
Figure 1 shows the basic architecture of two stage GaN MMIC power amplifier. The figure shows a two stage GaN MMIC Power Amplifier basic architecture with package.
The wideband MMIC GaN power amplifier comprises of driver stage and output stage along with selection of FET (Field-effect transistor) peripheries with the trade-off of Gain, Output Power and Power added efficiency. To meet this requirement, there is need of gallium nitride (GaN) High Electron Mobility Transistor (HEMT) based monolithic microwave integrated circuit (MMIC).
GaN has superior properties compared to silicon or gallium arsenide, including higher breakdown voltage, higher saturated electron drift velocity and higher thermal conductivity. GaN HEMTs also offer greater power density and wider bandwidths compared to Si and GaAs transistors.
The present invention provides wideband (S-C BAND) MMIC GaN Power Amplifier with die size of 4.5 X 4.8 mm (300) fabricated using high power 0.25um gate GaN technology manufactured on 100mm SiC substrates. This process offers power density 5W/mm and linear gain 18dB at 10GHz with drain current of 100mA/mm.
Figure 3 illustrates MMIC Die of 2 stage GaN Power Amplifier with dimension of 4.5 x 4.8 mm.
The MMIC GaN power amplifier consists of a driver stage and power stage with FET periphery of 6X150um (309) and 6X200um (310) respectively. Both the driver stage and Power stage have the parallel R-C stability circuit (301,302) to ensure the unconditional stability across the wide frequency range. Along with this, on chip and off chip decoupling capacitors (303, 304, 305, 306) are used to avoid low frequency oscillations.
To achieve impedance matching, this device comprises matching networks of input (311), intermediate (312) and output (313) by using reactive matching topology to provide wide bandwidth.
This power amplifier is a two stage GaN HEMT MMIC Power Amplifier, which operates from S-C band frequency ranges. The amplifier typically provides 25 dB of small signal gain and 30 W saturated output power with an associated power added efficiency of better than 35 %. The wideband amplifier’s input and output are internally matched to 50 Ohm. The amplifier requires bias from dedicated pins, (Vg and Vd). An external alumina substrate (200) consists of an inductor (201) connected between D1 and D2 to provide DC-RF isolation and resistor (202) connected between G1 and G2 to ensure the unconditional stability.
Figure 4 illustrates a RF/DC connection PCB in ceramic substrate.
The component has internal DC-decoupling on the gate and drain pins respectively. The present invention power amplifier is packaged in 6 pins lead frame format ceramic/metal flange package (100) enabling wide bandwidth to be achieved in a small foot print screw down package featuring a CMC (cu-mo-cu) base heat sink. The RF input and output connections (400) are gold plated to enable die attach at the next level assembly.
Figure 5 illustrates complete packaged MMIC GaN Power amplifier with RF input, RF output, source, drain and gate supply interconnections.
In one embodiment, the present invention relates to a two stage Wideband MMIC GaN Power amplifier consisting of an input matching network (311), intermediate matching network (312), output matching network (313), FETs in driver (309) and output stage (310) fabricated on 0.25 um GaN HEMT process and packaged in Ceramic/Metal Flange package to obtain following features, i.e., Operating band of Frequency: S-C band, Output Power:30W, Power Added Efficiency:35%, 25dB Small Signal Gain and Wide Bandwidth.
In another embodiment of the present invention, the MMIC contains a two-stage reactively matched amplifier design approach which consists of multi section L-C matching components enabling wide bandwidth with less insertion loss.
In another embodiment, an OFF-Chip Component circuit consists of spiral inductor and resistor fabricated on 10 mil alumina substrates and integrated in Ceramic/Metal Flange package. This circuit is used at top and bottom to ensure symmetry operation of the device.
In another embodiment, inductance is connected between drain stages of driver and output stage to reduce RF power leakage thereby enhancing Power, Gain and Efficiency.
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 wide band high power amplifier comprising:
a) a two-stage wideband MMIC GaN Power amplifier consisting of an input matching network (311), an intermediate matching network (312), an output matching network (313) configured to perform impedance matching of the amplifier; and
b) a FETs in driver (309) and output stage (310) fabricated on 0.25 um GaN HEMT process and packaged in Ceramic/Metal Flange package;
wherein the driver stage and the Power stage have the parallel R-C stability circuit (301,302) to ensure unconditional stability across the wide frequency range.
2. The wide band high power amplifier as claimed in claim 1, wherein an on chip and off chip decoupling capacitors (303, 304, 305, 306) is configured to prevent low frequency oscillations.
3. The wide band high power amplifier as claimed in claim 1, wherein the power amplifier comprises a matching network of input (311), intermediate (312) and output (313) by using reactive matching topology to provide wide bandwidth.
4. The wide band high power amplifier as claimed in claim 1, wherein the power amplifier is biased from dedicated pins, (Vg and Vd).
5. The wide band high power amplifier as claimed in claim 1, wherein an external alumina substrate (200) consists of an inductor (201) connected between D1 and D2 to provide DC-RF isolation and a resistor (202) connected between G1 and G2 to ensure the unconditional stability the power amplifier.
6. The wide band high power amplifier as claimed in claim 1, wherein the power amplifier is packaged in 6 pins lead frame format ceramic/metal flange package (100) enabling wide bandwidth to be achieved in a small foot print screw down package featuring a CMC (cu-mo-cu) base heat sink.
7. The wide band high power amplifier as claimed in claim 1, wherein the OFF-Chip comprises spiral inductor and resistor fabricated on 10 mil alumina substrates and integrated in Ceramic/Metal Flange package, where the inductor and the capacitor is mounted on top and bottom to ensure symmetry operation of the device.