Daniel Gryglewski

The 100W class A power amplifier for L-band T/R module

A balanced high-power amplifier with class A silicon bipolar transistors for an L-band T/R module for active phased array radar is described. The amplifier was designed for maximum power and minimum transmittance distortion. The obtained parameters of the amplifier are as follow: output power at 1dB compression P/sub 1 dB/>49 dBm, linear gain |S21|>10 dB, and transmittance deviations during the RF pulse: phase /spl Delta/arg(S21)<0.9/spl deg/ and /spl Delta/P/sub out/< 0.2 dB.

Temperature-dependent modeling of high power MESFET using thermal FDTD method

A temperature-dependent model of high power MESFET based on the small signal extraction methodology is presented. The temperature dependencies of the MESFET equivalent circuit elements derived from experimental results describing long-term thermal effects and short-term thermal effects have been modeled by means of FDTD method using chip dimensions. The verification of the proposed model shows an excellent agreement of the experimental results with the theoretical analysis.

S-band GaN PolHEMT power amplifier

Under PolHEMT project focused on AlGaN/GaN HEMT on truly bulk semi-insulating GaN substrate technology development a power amplifier using this type of polish transistor was designed and fabricated. The amplifier achieves the parameters as follow: output power at 1dB G.C.P. more than 31dBm, max power density of 4,15W/mm, small-signal gain |S21|>12,5dB, over a 2,5GHz to 3,5GHz frequency range.

An ultrawideband 1 to 6 GHz 0-IF radio receiver with 500 MHz of instantaneous bandwidth

This paper is related to the project of an ultrawideband radio receiver operating between 1 and 6 GHz with instantaneous bandwidth of 500 MHz. A single frequency conversion (0-IF) architecture is based on analog I/Q demodulator (ADL5380) and two channel 14-bit analog-to-digital converter (AD9680). Preliminary measurements of the receiver have been performed and presented in the paper. Key results include: noise figure NF < 7.5 dB, dynamic range over 62 dB (enhanced by frontend and baseband leveling circuitry), high linearity: IIP3 > 21 dBm.

Low phase noise synthesizer optimized for wideband 0-IF radio receiver

In this paper the performance of two wideband PLL frequency synthesizers realized with ADF5355 and HMC833 chips respectively has been compared. Both of them were investigated as a local oscillator for 0IF receiver operating from 1 GHz to 6 GHz. In order to provide required harmonics level below -40 dBc the final solution is based on the ADF5355 followed by a switched bank of four low pass filters. The phase noise level is better than -90 dBc @ 1 kHz and spurious are lower than -70 dBc.

Transverters for TDD and FDD ISM 2.4GHZ Radio Systems

The paper describes development of a technique and equipment to convert signals from TDD or FDD radio systems operating over popular ISM 2.4 GHz-band up to the less crowded, licensed 3.5GHz or 4.4GHz bands. The technique of bands conversion consists in a connection to the existing infrastructures RF up/down converter modules (transverter) with T/R switches or duplexer for TDD or FDD systems, respectively. Currently, the 3.5GHz FDD transverters cooperate in 17 locations with the IRT2000 digital radio access system used by El-net NETIA group and 4.4GHz TDD transverters work together with 802.11b WLAN AP utilized by Military Communication Institute.

A 100W ISM-2.45GHz band power test system

This paper describes development of solid-state microwave power test system (MPTS) operating over 2.3 to 2.6 GHz with the output power level of 100 W for industrial applications in material processing, and for designing of microwave power industrial equipment. The MPTS unit consists of four major parts: PLL synthesizer, high power solid-state amplifier, detector probes for return losses and leakage measurement and microcontroller. The MPTS system is able to operate in either single fixed-frequency regime, or in swept mode with self-tuning for minimum reflection of a heated load.

A 300W S-band solid-state transmitter

This paper describes the structure and the performance of a 300 W compact solid-state transmitter operating over 2.9 to 3.1 GHz, for radar and medical applications. The transmitter consists of three major parts: PLL-DDS synthesizer, pulse shaping circuit and multi-stage class-C amplifier. A 300 W peak power with a pulse width up to 50 /spl mu/s and 5% duty cycle was achieved by combining two 160 W amplifiers with Si-BJT using a balanced configuration. The output power level is controlled in 6 dB dynamic range by means of a DC supply block. The power droop during RF-pulse is less than 0.2 dB for 5% duty operation in the whole output power dynamic range. The synthesized VCO achieves more than 10/sup -7/ long-term stability including pulling effect and -75 dBc/Hz@1 kHz phase noise. In addition the spectrum requirements are also satisfied.

The optimization of the transmittance phase changes of power amplifiers for T/R module of active phased array radar

A method of limitation of the transmittance deviation during the RF pulse of power amplifiers for the T/R module of active phase array radar is described. The method is based on the load-pull technique and is examined using a GaAs MESFET transistor.

AlGaN/GaN High Electron Mobility Transistors on Semi-Insulating Ammono-GaN Substrates with Regrown Ohmic Contacts

AlGaN/GaN high electron mobility transistors on semi-insulating bulk ammonothermal GaN have been investigated. By application of regrown ohmic contacts, the problem with obtaining low resistance ohmic contacts to low-dislocation high electron mobility transistor (HEMT) structures was solved. The maximum output current was about 1 A/mm and contact resistances was in the range of 0.3–0.6 Ω·mm. Good microwave performance was obtained due to the absence of parasitic elements such as high access resistance.