A Novel LSB Discriminator for a 5 bit IFM Subsystem Based on Microstrip Band-Stop Filter

Abstract

The authors have studied a new way to design IFM (Instantaneous Frequency Measurement) subsystem. The method is based on band-stop filters. The IFM uses rectangular open loop resonators instead of delay lines. The resonance frequency is adjusted by resonator perimeter, that must be half guided wavelength, and also by coupling distance between the resonators and the main transmission line. A LSB (least significant bit) discriminator of an IFM subsystem with resolution of 62.5MHz is designed. The device has been fabricated on RT6010.2 substrate of thickness h=1.27mm. A full wave EM simulator is used to obtain the frequency response.

A Novel Fully Integrated 4-Bit IFM Subsystem Using Band-Stop Filters

“…The use of open-loop resonators to produce multiband-stop filters is an alternative solution to the use of delay lines, avoiding the reflections and couplings through the meanders and bends commonly used with delay lines to occupy less space [2], [3], [7]. The use of band-stop filters provides more control over the system resolution and further decreases the required simulation time of the whole structure, and additionally provides an output signal similar to the one produced by the use of delay line based interferometers [8]. Multiband-stop filters can be produced by coupling multiple open-loop resonators to a transmission line.…”

“…Multiband-stop filters can be produced by coupling multiple open-loop resonators to a transmission line. The compact multiband-stop filters are ideal to substitute interferometers based on delay lines, traditionally used in IFM subsystems [1], [8], which are bulky and heavy.…”

A 2 to 4 GHZ Instantaneous Frequency Measurement System Using Multiple Band-Pass Filters

“…A conventional IFM, measures the phase between the received signal and a delayed version of it to extract the frequency information. A delay line is used to generate the delayed signal, and a phase discriminator to measure the phase difference [3,4]. A phase discriminator is often implemented using power dividers, hybrid couplers, and square law detectors [5].…”

Interferometer Instantaneous Frequency Identifier

“…That resonator is placed near to a 50 Ω microstrip transmission line, which was designed with aid of quasi-static analysis and quasi-TEM approximation [8]- [9]. Fig.…”

“…As a good example, a coplanar interferometer based on interdigital delay line with different finger lengths, will be presented. Another example of interferometers, but now, implemented with micro strip multi-band-stop filters to obtain signals similar to those supplied by the interferometers was published recently and will be presented here as well [9,10].…”