# Miniaturized Arrow-Shaped Flexible Filter-Embedded Antenna for Industrial and Medical Applications
## 1 Introduction
Contrary to this, a filter integrated with the antenna structure is also a possible solution to this uprising challenge. The co-design of antennas and filters, also known as \"filtennas\", is gaining traction in wireless communication system design due to its potential for enhancing performance while minimizing size [27; 28]. Integrating filtering functionality with antennas or replacing the last resonator of a filter with an antenna allows for compact and efficient designs that meet the demands of modern wireless systems [29; 30]. These strategies help manage the trade-offs between size reduction and performance. One common approach involves etching slots, slits, or adding parasitic elements to the antenna [31; 32; 33; 34]. While these modifications can lead to size reduction, they may introduce drawbacks like reduced gain, altered polarization, and degraded radiation patterns. On the other hand, filters can provide high selectivity, improve out-of-band rejection (essential for minimizing interference), and help maintain antenna performance even in compact designs. Patch and monopole antennas are commonly employed for filtenna designs because of their simplicity and adaptability in integrating filtering functions [35; 36; 37; 38; 39; 40]. In the same way, the work in [41] investigated a uniplanar differential-fed transparent circular filtenna with defected ground structure. In [42], another design approach involving an inverted microstrip gap waveguide technology is employed to design filtenna. Although this design integrates the co-planar EBG filters with gap waveguide technology to avoid unwanted radiation and to reduce interfering signals, this multilayered approach involves more design and fabrication complexity. Although the antennas presented in these works successfully reject spurious radiation, the addition of filters increases the complexity and size of the design, making it less amenable to miniaturization and integration. Other approaches to harmonic suppression have been discussed in the literature, including the introduction of photonic band gap structures [43], tuning stubs [44], etc. However, the disadvantage of the structure being too bulky still persists. Hence, the focus on combining antennas and filters is part of the broader effort to develop smaller, more efficient wireless communication components. These innovations are crucial for modern communication systems that demand high performance, compactness, and functionality in constrained environments. To summarize, the flexible electronics market requires the use of efficient non-rigid antennas characterized by wide bandwidth, good radiation characteristics, and good matching. On the other hand, the option of harmonic suppression must be incorporated in order to reduce interference while keeping a miniaturized profile in order to facilitate the integration of the antennas into miniaturized components. In this scenario, this work presents a flexible fractal antenna, characterized by a compact profile, and provided with the characteristic of harmonic rejection. The antenna is supposed to operate at a frequency ranging from 2.276 to 2.72 GHz, effectively covering the ISM band. The key contribution of the proposed work is as follows:  
1. The proposed antenna consists of simple configurations that significantly reduce the fabrication errors for massive production. 2. Compact size and high gain as compared with related products make it a strong candidate for targeted applications. 3. Stable performance is achieved in both rigid and conformal scenarios. 4. Along with confirmability, the proposed antenna offers filtering properties that are validated using measured results.