Design of a Ku-Band Filtenna With a Modified Slot Structure for Satellite Communication Applications

Abstract

A Filtenna, also known as a Filter-Antenna Module, is a ground-breaking hybrid device that combines the functions of a filter and an antenna in a single structure. The filtering function is realized through the effective reactive behavior of the integrated parallel-coupled dual-line bandpass filter, which provides frequency selectivity while enabling the antenna to radiate at the desired frequencies. The presented design is an ultra-wideband antenna with an inset feeding network and a dual-line coupling structure that serves as a bandpass filter structure. This construction is augmented with a defected ground structure that uses a shaped slot designed to support narrowband applications, namely Ku-band uplink and downlink satellite communications. This is because the dual-line coupling structure provides stronger coupling between closely spaced lines, enabling precise frequency control. The filtenna is built on a Rogers RT/Duroid 3010 substrate with a thickness of 0.635 mm and a dielectric constant ξr of 3.4, giving it excellent performance and reliability. High-frequency structure simulator software was used to optimize the design and achieve the required operational characteristics. The simulation is confirmed by experimental results that demonstrate that the filtenna is able to work at 11.5 GHz and 14 GHz, which reaches a reflection coefficient ($S_{11}$) of below −20 dB. The gain values observed are 4.18 dB and 3.59 dB at these respective frequencies, which is good performance. The test was conducted in an anechoic chamber and using a network analyzer (Agilent N5247A: A.09.90.02) to get the correct electromagnetic measurements. The proposed design is compact, with physical dimensions of 20.56 × 16.98 mm (total built-up area of less than 348 mm²), making it highly advantageous for space-constrained Ku-band satellite communication applications, making it highly advantageous for space-constrained Ku-band satellite communication applications. This innovative approach not only reduces system complexity by merging filtering and radiating functions but also enhances overall efficiency, setting a benchmark for future antenna-filter integration designs.