Switchable Instantaneous Frequency Measurement by Optical Power Monitoring Based on DP-QPSK Modulator

We propose and analyze an instantaneous frequency measurement system using optical power monitoring technique with improved resolution. The primary component employed in the proposal is a DP-QPSK modulator which is used to modulate the microwave signal with a designed time delay and phase shifting. Then the generated optical signal is sent to polarization beam splitter (PBS) via polarization controller (PC). Thanks to the complementary transmission nature of polarization interference introduced by PBS, the frequency information is converted to the optical power and the relationship between the amplitude comparison function (ACF) and microwave frequency to be measured is established. Thus, the frequency of the microwave signal could be easily measured through monitoring the optical powers of the two output ports of the PBS. Furthermore, by adjusting the DC biases of the DP-QPSK modulator instead of changing the electrical delay, the measurement range and resolution can be switched. In this paper, the basic principle of the instantaneous frequency measurement system is derived in detail, and simulation has been performed to investigate the resolution, the measurement range and the impact of imperfection devices. The proposed scheme is wavelength independent and measurement range switchable, which can avoid the laser wavelength drifting problem and greatly increase the system flexibility.

Photonic RF and Microwave Photonic Channelizers based on Kerr Micro-combs

We review recent work on broadband RF channelizers based on integrated optical frequency Kerr micro-combs combined with passive micro-ring resonator filters, with microcombs having channel spacings of 200GHz and 49GHz. This approach to realizing RF channelizers offers reduced complexity, size, and potential cost for a wide range of applications to microwave signal detection.

Monolithic transistor switch for microwave radiometry

Modern medical microwave diagnostic equipment requires the application of solutions related to the compactness of the developed devices and high performance. Ensuring these requirements is possible by using a modern semiconductor component base based on A3B5 compounds. One of the promising materials for this purpose is gallium nitride. The paper presents the design and manufacturing technology of one of the main control elements of the microwave signal in microwave radiothermometer - monolithic AlGaN/GaN/SiC HEMT SPDT transistor switch.

Development of a fiber-optic microwave signal transmissionsystem for an X-band receiving module with dual frequencyconversion

The article discusses the use of double frequency conversion in the receiving module of the radar. To solve the resulting interference in the feeder paths, it is proposed to use a fiber- optic transmission system. The results of experimental investigations are presented.