Reconfigurable Frequency Discriminator Based on Fractal Delay Line

Abstract

A new compact Reconfigurable Frequency Measurement (RFM) device, based on interferometry is presented in this paper. The device combines the advantages of reconfigurability and fractal geometry. The interferometer uses a Wilkinson power divider connected to two microstrip delay lines; one of these corresponds to the second iteration of the Hilbert fractal curve. PIN diode switches are properly placed in the fractal delay line to achieve a 3-bit circuit, which operates in the 2.7-4.5 GHz range. The design and simulations presented are done using a full wave EM simulator, and the frequency responses of the circuit are then shown and compared to measured results.

Microwave Interference Techniques for Frequency Measurement and Filters

“…The signal-interference technique also presents a new approach to filter design with sharp-rejection stopbands. These highly-selective multi-band and wide-band filters are respectively applied in systems that support multiple standards at the same time [5] and broad-band receivers (e.g., wide-band EW, ultra-wideband radar and high data-rate communication systems [4]).…”

“…In [4], an even more compact RFM interferometer is described. The interferometer delay lines are based on the Hilbert fractal curve, with space filling properties allowing to increase the delay line length in one overall delimited area.…”

“…Microwave interference is useful to design microwave devices with filtering properties, such as interferometers for frequency measurement applications [1][2][3][4], wide-band [5,6] and dual-band [7] bandpass filters among others. The core part of these devices is the interferometer section.…”

Frequency discriminator design phase formula with experimental verification for frequency measurement systems with uniform sub‐band resolution

“…The phase difference can be formulated to produce uniform sub-bands for frequency identification. Recently, reconfigurable frequency measurement (RFM) receivers using phase shifters [10][11][12][13] have the advantage of low-power consumption and miniaturization because fewer electronic components are required, compared to IFM receivers. The formulated phase differences are useful for the FD design and implementation.…”

A neuro‐based approach to designing a Wilkinson power divider

“…In a different size‐efficient approach, fractal geometries have been proposed to enlarge the electric length of the transmission lines, leading to miniaturized microstrip components . A 3‐terminal, 2‐pole bandpass filter and two 3‐pole lowpass filters are used to replace the two quarter‐wavelength transformers in a standard Wilkinson power .…”