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Purpose The purpose of this paper is to propose a new design strategy to enhance the bandwidth and efficiency of the power amplifier. Design/methodology/approach To realize the introduced design strategy, a power amplifier was designed using TSMC CMOS 0.18um technology for operating in the Ka-band, i.e. the frequency range of 26.5-40 GHz. To design the power amplifier, first, a power divider (PD) with a very wide bandwidth, i.e. 1-40 GHz, was designed to cover the whole Ka-band. The designed Doherty power amplifier consisted of two different amplification paths called main and auxiliary. To amplify the signal in each of the two pathways, a cascade distributed power amplifier was used. The main reason for combining the distributed structure and cascade structure was to increase the gain and linearity of the power amplifier. Findings Measurements results for designed power dividers are in good agreement with simulations results. The simulation results for the introduced structure of the power amplifier indicated that the gain of the proposed power amplifier at the frequency of 26-35 GHz was more than 30 dB. The diagram of return loss at the input and output of the power amplifier in the whole Ka-band was less than −8dB. The maximum power-added efficiency (PAE) of the designed power amplifier was 80%. The output P1dB of the introduced structure was 36 dB and the output power of the power amplifier was 36 dBm. Finally, the IP3 value of the power amplifier was about 17 dB. Originality/value The strategy presented in this paper is based on the usage of Doherty and distributed structures and a new wideband power divider to benefit from their advantages simultaneously.

Obtaining transfer function of electrical, mechanical, etc. systems can provide this possibility for the researchers to investigate the behaviours of desired systems based on different inputs in various working circumstances without need to laboratory equipment which it results in lower consumption of time and expense. The aim of current research is obtaining the existing gyroscopic stabilizer transfer function. The way we used in this article is the newest laboratory way for obtaining transfer function of gyroscopic stabilizers. This aim is achieved by using laboratory equipment such as a two degrees of freedom gyro stabilized platform that an imaging system is installed on it as the load, target simulator table with one degree of freedom, and electronic conversion board of RS488 to RS232 serial communication standard, etc. An arbitrary input is introduced to under test system and the system behaviour toward the introduced input is saved and finally the transfer function of existing two degrees of freedom gyro stabilized platform is obtained using system identification toolbox in MATLAB. At the end of this article, the step response of transfer function obtained through the desired experiment in the laboratory compared with the step response obtained through simulations that a %10 difference between them is observed.

Obtaining transfer function of electrical, mechanical, etc. systems can provide this possibility for the researchers to investigate the behaviours of desired systems based on different inputs in various working circumstances without need to laboratory equipment which it results in lower consumption of time and expense. The aim of current research is obtaining the existing gyroscopic stabilizer transfer function. The way we used in this article is the newest laboratory way for obtaining transfer function of gyroscopic stabilizers. This aim is achieved by using laboratory equipment such as a two degrees of freedom gyro stabilized platform that an imaging system is installed on it as the load, target simulator table with one degree of freedom, and electronic conversion board of RS488 to RS232 serial communication standard, etc. An input which excites all modes (search and track) of two degrees of freedom gyro stabilized platform is introduced to under test system and the system behaviour toward the introduced input is saved and finally the transfer function of existing two degrees of freedom gyro stabilized platform is obtained using system identification toolbox in MATLAB. At the end of this article, the step response of transfer function obtained through the desired experiment in the laboratory compared with the step response obtained through simulations that a %10 difference between them is observed.