JLAB upgrade program requires a ~8 kW, 1497 MHz amplifier operating at more than 55-60% efficienc... more JLAB upgrade program requires a ~8 kW, 1497 MHz amplifier operating at more than 55-60% efficiency, and 8 kW CW power to replace up to 340 klystrons. One of possibilities for the klystron replacement is usage of high electron mobility packaged GaN transistors applied in array of highly efficient amplifiers using precise in-phase, low-loss combiners-dividers. Design features and challenges related to amplifier modules and radial multi-way dividers/combiners are discussed including HFSS simulations and measurements.
2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), 2018
This paper describes a high output power (133W) inverse class-F (class-F−1) GaN HEMT power amplif... more This paper describes a high output power (133W) inverse class-F (class-F−1) GaN HEMT power amplifier (PA) for space applications. The PA operates at 1.227GHz-the L2C second civilian GPS signal operation frequency. Harmonic controlling matching networks are designed to achieve class-F−1 current and voltage waveforms at the intrinsic drain. High efficiency is achieved by using harmonic source and load-pull tuning to design the input and output matching networks. The fo matching is performed using a low-Z single-section transformer. Harmonic terminations for 2fo and 3fo are realized using shunt transmission lines placed at optimal offsets from the drain. These matching networks are fine-tuned using a network analyzer. The overall PA performance was tested under different DC biases with swept input power. The best performance is achieved with a bias of Vds=50V, Vgs=−3V and Pin=32dBm where the PA exhibits 133W output at 42% power-added efficiency (PAE).
2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), 2018
Energy harvesting and wireless power transfer to power small, low-power and autonomous devices ha... more Energy harvesting and wireless power transfer to power small, low-power and autonomous devices have recently attracted numerous research studies. Due to the lack of energy supplies, DC to DC converters with multiple inputs have been studied to harvest different energy sources simultaneously. In this paper, a proposed pulse skipping modulation method is used to control a multiple input buck boost converter with the output power from 7 μW–700 μW. The DC to DC converter can achieve a high efficiency of 83.3% at 23.6 μA load current, and the highest efficiency is up to 89.1% at 255 μA current load. The control method offers the flexibility and adaptability in maximum power point tracking and input power contribution. The paper investigates a completed energy harvesting system including a solar cell and 915 MHz RF source and power management circuits.
An active microwave frequency tripler using an AlGaN/GaN HEMT device is developed. This is the fi... more An active microwave frequency tripler using an AlGaN/GaN HEMT device is developed. This is the first reported frequency tripler implemented in GaN technology. Design of the frequency tripler is performed using a high-accuracy, multi-harmonic, wideband model which predicts the effects of self-heating and charge-trapping. A method of determining the optimal load and source networks using harmonic load-/source-pull simulations and synthesizing using harmonic reflectors is described. The tripler upconverts fo=3.33GHz to 10GHz to achieve a maximum power of +30.0dBm (1.0W). As such, it provides multiplied powers which are approximately 50 times greater than those previously reported.
JLab upgrade program foresees new CW amplifiers operating at 1497 MHz and significantly increased... more JLab upgrade program foresees new CW amplifiers operating at 1497 MHz and significantly increased efficiency vs. existing VKL-7811 klystron. One of possibilities for the replacement is usage of high electron mobility packaged GaN transistors applied in array of highly efficient amplifiers using precise in-phase, low-loss combiners-dividers. We present here performance of novel, compact 300 W pallets developed at Microsemi specifically for this project including their new GaN transistor, as well as significantly upgraded divider and combiner. Design features and challenges related to amplifier modules (pallets), broadband 21-way dividers/combiners, as well construction and assembling of the entire system are discussed including measurements.
The far-field electromagnetic radiation patterns of different dipole antennas used for an RF ener... more The far-field electromagnetic radiation patterns of different dipole antennas used for an RF energy harvesting necklace for smart jewelry are studied. Rigid Vee, V-shaped copper and flexible silver-ink dipoles are explored with and without a human body phantom. Measurements demonstrate the advantages of Vee or V-shaped dipoles for harvesting more RF energy at the sides of the human body compared to a straight dipole. The flexible RF energy harvesting necklace can produce 72.2 µW at 5.3 m from a 3 W EIRP 915 MHz RF transmitter when worn by a person.
2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), 2018
This paper describes a high output power (133W) inverse class-F (class-F−1) GaN HEMT power amplif... more This paper describes a high output power (133W) inverse class-F (class-F−1) GaN HEMT power amplifier (PA) for space applications. The PA operates at 1.227GHz-the L2C second civilian GPS signal operation frequency. Harmonic controlling matching networks are designed to achieve class-F−1 current and voltage waveforms at the intrinsic drain. High efficiency is achieved by using harmonic source and load-pull tuning to design the input and output matching networks. The fo matching is performed using a low-Z single-section transformer. Harmonic terminations for 2fo and 3fo are realized using shunt transmission lines placed at optimal offsets from the drain. These matching networks are fine-tuned using a network analyzer. The overall PA performance was tested under different DC biases with swept input power. The best performance is achieved with a bias of Vds=50V, Vgs=−3V and Pin=32dBm where the PA exhibits 133W output at 42% power-added efficiency (PAE).
The work presents a light weight and compact solid-state power amplifier (SSPA) using GaN technol... more The work presents a light weight and compact solid-state power amplifier (SSPA) using GaN technology for L1 band (1.575GHz) GPS applications. Due to immature development of GaN transistor modeling, the PA is designed to operate in Class F mode by using a combination of harmonic load-pull simulations and data-based characterization to achieve high PAE. Additionally, the paper will discuss the solutions to the challenges of thermal management and input matching network design. A hybrid circuit realization achieves Pout=102W, ETA=68% and PAE=66% with gain=15.1dB under 3dB gain compression in CW operation.
The far-field electromagnetic radiation patterns of different dipole antennas used for an RF ener... more The far-field electromagnetic radiation patterns of different dipole antennas used for an RF energy harvesting necklace for smart jewelry are studied. Rigid Vee, V-shaped copper and flexible silver-ink dipoles are explored with and without a human body phantom. Measurements demonstrate the advantages of Vee or V-shaped dipoles for harvesting more RF energy at the sides of the human body compared to a straight dipole. The flexible RF energy harvesting necklace can produce 72.2 µW at 5.3 m from a 3 W EIRP 915 MHz RF transmitter when worn by a person.
The work presents a light weight and compact solid-state power amplifier (SSPA) using GaN technol... more The work presents a light weight and compact solid-state power amplifier (SSPA) using GaN technology for L1 band (1.575GHz) GPS applications. Due to immature development of GaN transistor modeling, the PA is designed to operate in Class F mode by using a combination of harmonic load-pull simulations and data-based characterization to achieve high PAE. Additionally, the paper will discuss the solutions to the challenges of thermal management and input matching network design. A hybrid circuit realization achieves Pout=102W, ETA=68% and PAE=66% with gain=15.1dB under 3dB gain compression in CW operation.
2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), 2018
Energy harvesting and wireless power transfer to power small, low-power and autonomous devices ha... more Energy harvesting and wireless power transfer to power small, low-power and autonomous devices have recently attracted numerous research studies. Due to the lack of energy supplies, DC to DC converters with multiple inputs have been studied to harvest different energy sources simultaneously. In this paper, a proposed pulse skipping modulation method is used to control a multiple input buck boost converter with the output power from 7 μW–700 μW. The DC to DC converter can achieve a high efficiency of 83.3% at 23.6 μA load current, and the highest efficiency is up to 89.1% at 255 μA current load. The control method offers the flexibility and adaptability in maximum power point tracking and input power contribution. The paper investigates a completed energy harvesting system including a solar cell and 915 MHz RF source and power management circuits.
An active microwave frequency tripler using an AlGaN/GaN HEMT device is developed. This is the fi... more An active microwave frequency tripler using an AlGaN/GaN HEMT device is developed. This is the first reported frequency tripler implemented in GaN technology. Design of the frequency tripler is performed using a high-accuracy, multi-harmonic, wideband model which predicts the effects of self-heating and charge-trapping. A method of determining the optimal load and source networks using harmonic load-/source-pull simulations and synthesizing using harmonic reflectors is described. The tripler upconverts fo=3.33GHz to 10GHz to achieve a maximum power of +30.0dBm (1.0W). As such, it provides multiplied powers which are approximately 50 times greater than those previously reported.
JLAB upgrade program requires a ~8 kW, 1497 MHz amplifier operating at more than 55-60% efficienc... more JLAB upgrade program requires a ~8 kW, 1497 MHz amplifier operating at more than 55-60% efficiency, and 8 kW CW power to replace up to 340 klystrons. One of possibilities for the klystron replacement is usage of high electron mobility packaged GaN transistors applied in array of highly efficient amplifiers using precise in-phase, low-loss combiners-dividers. Design features and challenges related to amplifier modules and radial multi-way dividers/combiners are discussed including HFSS simulations and measurements.
2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), 2018
This paper describes a high output power (133W) inverse class-F (class-F−1) GaN HEMT power amplif... more This paper describes a high output power (133W) inverse class-F (class-F−1) GaN HEMT power amplifier (PA) for space applications. The PA operates at 1.227GHz-the L2C second civilian GPS signal operation frequency. Harmonic controlling matching networks are designed to achieve class-F−1 current and voltage waveforms at the intrinsic drain. High efficiency is achieved by using harmonic source and load-pull tuning to design the input and output matching networks. The fo matching is performed using a low-Z single-section transformer. Harmonic terminations for 2fo and 3fo are realized using shunt transmission lines placed at optimal offsets from the drain. These matching networks are fine-tuned using a network analyzer. The overall PA performance was tested under different DC biases with swept input power. The best performance is achieved with a bias of Vds=50V, Vgs=−3V and Pin=32dBm where the PA exhibits 133W output at 42% power-added efficiency (PAE).
2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), 2018
Energy harvesting and wireless power transfer to power small, low-power and autonomous devices ha... more Energy harvesting and wireless power transfer to power small, low-power and autonomous devices have recently attracted numerous research studies. Due to the lack of energy supplies, DC to DC converters with multiple inputs have been studied to harvest different energy sources simultaneously. In this paper, a proposed pulse skipping modulation method is used to control a multiple input buck boost converter with the output power from 7 μW–700 μW. The DC to DC converter can achieve a high efficiency of 83.3% at 23.6 μA load current, and the highest efficiency is up to 89.1% at 255 μA current load. The control method offers the flexibility and adaptability in maximum power point tracking and input power contribution. The paper investigates a completed energy harvesting system including a solar cell and 915 MHz RF source and power management circuits.
An active microwave frequency tripler using an AlGaN/GaN HEMT device is developed. This is the fi... more An active microwave frequency tripler using an AlGaN/GaN HEMT device is developed. This is the first reported frequency tripler implemented in GaN technology. Design of the frequency tripler is performed using a high-accuracy, multi-harmonic, wideband model which predicts the effects of self-heating and charge-trapping. A method of determining the optimal load and source networks using harmonic load-/source-pull simulations and synthesizing using harmonic reflectors is described. The tripler upconverts fo=3.33GHz to 10GHz to achieve a maximum power of +30.0dBm (1.0W). As such, it provides multiplied powers which are approximately 50 times greater than those previously reported.
JLab upgrade program foresees new CW amplifiers operating at 1497 MHz and significantly increased... more JLab upgrade program foresees new CW amplifiers operating at 1497 MHz and significantly increased efficiency vs. existing VKL-7811 klystron. One of possibilities for the replacement is usage of high electron mobility packaged GaN transistors applied in array of highly efficient amplifiers using precise in-phase, low-loss combiners-dividers. We present here performance of novel, compact 300 W pallets developed at Microsemi specifically for this project including their new GaN transistor, as well as significantly upgraded divider and combiner. Design features and challenges related to amplifier modules (pallets), broadband 21-way dividers/combiners, as well construction and assembling of the entire system are discussed including measurements.
The far-field electromagnetic radiation patterns of different dipole antennas used for an RF ener... more The far-field electromagnetic radiation patterns of different dipole antennas used for an RF energy harvesting necklace for smart jewelry are studied. Rigid Vee, V-shaped copper and flexible silver-ink dipoles are explored with and without a human body phantom. Measurements demonstrate the advantages of Vee or V-shaped dipoles for harvesting more RF energy at the sides of the human body compared to a straight dipole. The flexible RF energy harvesting necklace can produce 72.2 µW at 5.3 m from a 3 W EIRP 915 MHz RF transmitter when worn by a person.
2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), 2018
This paper describes a high output power (133W) inverse class-F (class-F−1) GaN HEMT power amplif... more This paper describes a high output power (133W) inverse class-F (class-F−1) GaN HEMT power amplifier (PA) for space applications. The PA operates at 1.227GHz-the L2C second civilian GPS signal operation frequency. Harmonic controlling matching networks are designed to achieve class-F−1 current and voltage waveforms at the intrinsic drain. High efficiency is achieved by using harmonic source and load-pull tuning to design the input and output matching networks. The fo matching is performed using a low-Z single-section transformer. Harmonic terminations for 2fo and 3fo are realized using shunt transmission lines placed at optimal offsets from the drain. These matching networks are fine-tuned using a network analyzer. The overall PA performance was tested under different DC biases with swept input power. The best performance is achieved with a bias of Vds=50V, Vgs=−3V and Pin=32dBm where the PA exhibits 133W output at 42% power-added efficiency (PAE).
The work presents a light weight and compact solid-state power amplifier (SSPA) using GaN technol... more The work presents a light weight and compact solid-state power amplifier (SSPA) using GaN technology for L1 band (1.575GHz) GPS applications. Due to immature development of GaN transistor modeling, the PA is designed to operate in Class F mode by using a combination of harmonic load-pull simulations and data-based characterization to achieve high PAE. Additionally, the paper will discuss the solutions to the challenges of thermal management and input matching network design. A hybrid circuit realization achieves Pout=102W, ETA=68% and PAE=66% with gain=15.1dB under 3dB gain compression in CW operation.
The far-field electromagnetic radiation patterns of different dipole antennas used for an RF ener... more The far-field electromagnetic radiation patterns of different dipole antennas used for an RF energy harvesting necklace for smart jewelry are studied. Rigid Vee, V-shaped copper and flexible silver-ink dipoles are explored with and without a human body phantom. Measurements demonstrate the advantages of Vee or V-shaped dipoles for harvesting more RF energy at the sides of the human body compared to a straight dipole. The flexible RF energy harvesting necklace can produce 72.2 µW at 5.3 m from a 3 W EIRP 915 MHz RF transmitter when worn by a person.
The work presents a light weight and compact solid-state power amplifier (SSPA) using GaN technol... more The work presents a light weight and compact solid-state power amplifier (SSPA) using GaN technology for L1 band (1.575GHz) GPS applications. Due to immature development of GaN transistor modeling, the PA is designed to operate in Class F mode by using a combination of harmonic load-pull simulations and data-based characterization to achieve high PAE. Additionally, the paper will discuss the solutions to the challenges of thermal management and input matching network design. A hybrid circuit realization achieves Pout=102W, ETA=68% and PAE=66% with gain=15.1dB under 3dB gain compression in CW operation.
2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), 2018
Energy harvesting and wireless power transfer to power small, low-power and autonomous devices ha... more Energy harvesting and wireless power transfer to power small, low-power and autonomous devices have recently attracted numerous research studies. Due to the lack of energy supplies, DC to DC converters with multiple inputs have been studied to harvest different energy sources simultaneously. In this paper, a proposed pulse skipping modulation method is used to control a multiple input buck boost converter with the output power from 7 μW–700 μW. The DC to DC converter can achieve a high efficiency of 83.3% at 23.6 μA load current, and the highest efficiency is up to 89.1% at 255 μA current load. The control method offers the flexibility and adaptability in maximum power point tracking and input power contribution. The paper investigates a completed energy harvesting system including a solar cell and 915 MHz RF source and power management circuits.
An active microwave frequency tripler using an AlGaN/GaN HEMT device is developed. This is the fi... more An active microwave frequency tripler using an AlGaN/GaN HEMT device is developed. This is the first reported frequency tripler implemented in GaN technology. Design of the frequency tripler is performed using a high-accuracy, multi-harmonic, wideband model which predicts the effects of self-heating and charge-trapping. A method of determining the optimal load and source networks using harmonic load-/source-pull simulations and synthesizing using harmonic reflectors is described. The tripler upconverts fo=3.33GHz to 10GHz to achieve a maximum power of +30.0dBm (1.0W). As such, it provides multiplied powers which are approximately 50 times greater than those previously reported.
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