# A Frequency-Selective Reconfigurable Antenna for Wireless Applications in the S and C Bands
A reconfigurable MIMO antenna using RF MEMS switches is introduced in [13] with resonances from 800 MHz to 5.5 GHz. In [14], a frequency and pattern reconfigurable antenna is presented. A single PIN diode provided two modes, resonating at (1) 2.47 and 5.36 GHz, or (2) 3.8 GHz. Another frequency and pattern reconfigurable antenna proposed in [15] is based on three PIN diodes. The radiating element is a double-open-ring patch, and the resonant frequencies lie between 1.9 and 5.6 GHz. A reconfigurable antenna that can rotate its radiation pattern between \(-36^{\circ}\) and \(+36^{\circ}\) is presented in [16]. The antenna operates in the 5 GHz band, and the pattern reconfiguration is achieved by a feeding network using sixteen PIN diodes. The authors of [17] introduce a polarization reconfigurable antenna operating in the 2-3 GHz region. By varying the capacitance of four varactor diodes using a voltage up to 7.5 V, the polarization changes between right- or left-handed circular, horizontal, and vertical. Another polarization reconfigurable antenna switching between right-hand and left-hand circular polarization based on two PIN diodes is presented in [18], being appropriate for 5 G applications in the 3.5 GHz band. A phase change material, Germanium Telluride (GeTe), is used for a polarization reconfigurable antenna in [19] for applications in the 30 GHz band. By irradiating ultraviolet (UV) short laser pulses, the material switches between an insulating (OFF) and a metallic (ON) state. As a result, the antenna's polarization transitions between linear and circular, right or left-handed. An intriguing device, for absorption and conversion of electromagnetic energy, is presented in [20]. It is based on a four-ring multi-resistance unit, and it can be used as an energy harvester, converting microwave energy into thermal energy and eventually electrical energy. Its efficiency at 5.8 GHz is 99.5%. Finally, a frequency reconfigurable antenna, intended for cognitive radio applications, is shown in [21]. It operates on a wide band between 2.63 and 3.7 GHz, and it utilizes 12 PIN diodes on the ground plane. Most of the available literature concerning antenna reconfiguration characteristics via PIN diodes has so far concentrated on two or more PIN diodes [10; 11; 12; 15; 18; 21; 22; 23; 24; 25; 26]. On the other hand, fewer studies have been published with only one PIN diode [14; 27; 28]. In the present work, a single PIN diode greatly simplifies the design, the implementation, and the cost of the antenna. At the same time, the experimental results show a compact reconfigurable antenna with three dominant resonance frequencies at 2.07, 4.63, and 6.22 GHz and a wide bandwidth range where several wireless protocols, including IoT, are crowded into these frequency bands. Furthermore, such antenna technology could have a huge effect on military applications. Imagine a UAV/USV (unmanned aerial/surface vehicle) that incorporates a large number of small printed reconfigurable antennas on its structure that could act as an array of antennas, without or even with symmetry, exhibiting profound effects such as the ability to scan a beam with low alteration in either the beam width or the side lobe level. Additionally, a phased array could contain a considerable number of reconfigurable antennas. So, there is a boosted ability of an electronically controlled scheme, while creating a smart-radio beam that could be steered toward different directions and with different frequencies without physical movement. Considering the aforementioned in relation to the simplicity of implementing the suggested antenna, we can understand the impact on long and short communications (LoRa and SRC). The presented antenna was designed for integration into a high-precision signal power measurement setup, akin to the one detailed in [29]. This setup serves the purpose of gathering data about rain-induced attenuation. The investigation of rain rate through signal attenuation measurements has garnered significant interest in recent years [30].