Design and implementation of miniaturized RF filters used in communication applications

What is it about?

The objective of this paper is to propose a design for a simple multiband band-pass filter used in modern communications applications. The main idea of ​​the design is to choose an ultra-wide bandpass (UWB) filter and add several quarter-wavelength links to the UWB design. These quarter-wavelength links will act as band-stop filters. Some frequencies that were previously calculated will be stopped or rejected through the correct selection of both lengths. And the location of the links. This will create passbands between the rejected frequencies to create a multi-band pass filter. Reduce the cost of the filter by using a cheap insulator such as FR-4, which will reduce the cost of the filter and make it suitable for low-cost applications.After selecting a UWB band-pass filter, four quarter-wavelength links were added. These connectors are designed for specific rejection frequencies to produce a four-band pass filter with center band frequencies of 2.66, 3.76, 5.0 and 6.5 GHz. These frequencies serve the need for WLAN and WiMAX. The plate used to design the filter is FR-4 with a relative tolerance of 4.3 and a thickness of 1.5 mm. The filter dimensions were 0.35λg×0.48λg, where λg is due to the lowest resonant frequency. In the end, a prototype of the proposed filter was manufactured and measured. We obtained good results and there was agreement between the simulated and measured results

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