The instantaneous measurement of RF & microwave frequencies is widely used in electronic warfare (EW) for the determination of unknown signals over a broad frequency band. This paper presents an enhanced frequency measurement accuracy using three stages of novel RF frequency discriminator (FD) for RF front-end IFM Receivers. The appropriate structure of the designed frequency discriminator is implemented using a conventional PCB fabrication process. The frequency discriminator consists of two different hybrid layouts and one Wilkinson power divider, and all these components are implemented in microstrip technology, which is particularly important due to lower cost and easy integration into the PCB. To demonstrate the feasibility of the proposed structure, an RF-FE instantaneous frequency measurement (IFM) receiver has been realized based on 3-stage RF frequency discriminator. Simulation and measurement results have shown a frequency measurement accuracy less than 1 MHz (RMS) over the entire S-band.
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