# A Metamaterial Inspired AMC Backed Dual Band Antenna for ISM and RFID Applications
## 1 Introduction
A dual band metamaterial-inspired antenna shows reliable impedance bandwidth, radiation pattern and gain compatible for Monolithic microwave circuit (MMIC) technology [10]. In [11], a bowtie dual band antenna loaded by AMC ground plane was used for RFID applications. In combination with SRR, co-polarization and cross polarization of radiation patterns produce dual band characteristics [12]. Conventional microstrip patch antennas are limited by low gain and low efficiency, but short pins can overcome these limitations [13]. In [14], the proposed antenna was designed to reside in the frequency bands (860-960 and 902-928 MHz) for UHF RFID applications. A split ring resonator, which is metamaterial having two concentric metallic rings with splits in both rings, was a key element to achieve antenna miniaturization [15]. A rectangular microstrip antenna with an inverted E-slot and U-slot having the size 35.05 \(\times\) 18.24 \(\times\) 1.6 mm\({}^{3}\) offering improved gain, radiation efficiency with low cost, controlled radiation characteristics, and with a single layer design suitable for S-band, C-band, and wireless applications was reported in [16]. By using an Electric-inductive- Capacitive (ELC) resonator, a dual band with improved return loss characteristics can be obtained along the E-plane and H-plane and negative permeability property of metamaterial was described in [17]. The physical parameters of the ground plane width and split gap of the SRR were varied to achieve optimum resonance with size 31 \(\times\) 25 \(\times\) 1.6 mm\({}^{3}\) for WiMAX and WAVE applications [18]. A dual band microstrip antenna with two electrically coupled patches operating at 38 GHz and 60 GHz exhibited good performance regarding the output parameters, like gain bandwidth, radiation pattern, and efficiency, and is suitable for 5G mobile communication with excellent diversity schemes [19]. A MIMO-based Dielectric Resonator antenna (DRA) resonating at 28 GHz and 38 GHz reduces coupling without affecting the key parameters like gain, impedance matching, radiation pattern, efficiency, and is suitable for 5G mobile handset [20]. An impedance matched electronic circuit-based absorber was designed for the enhancement of gain in 5G applications. This metamaterial absorber resonated at 24 GHz and 28 GHz frequencies, based on the total inductance given by the meander line structure [21]. A low-profile wideband AMC-backed log-periodic meandered dipole array (LPMDA) antenna with improved gain and constant wideband characteristics was reported for communication system applications in UAVs and aircraft [22]. A dual band monopole antenna and a polarization rotation artificial magnetic conductor (PRAMC) was enabled, backward radiation was alleviated, and dyadic reflection coefficient analysis was employed to understand the operating mechanism, which is suitable for Wi-max and ISM applications [23]. The performance comparison of different compact antennas (conventional, EBG-based, and SRR-based) along with specific absorption rate (SAR) analysis suggests that they are well-suited for biomedical sensors, to work at 2.4 GHz and 5.8 GHz dual band frequencies [24]. A fully textile dual band logo antenna integrated with a reflector for application in IoT wearable devices achieves improvement in radiation, robustness, and efficiency both in free space and on humans, notebook, paper, and laptop phantom at dual band frequencies [25]. In this paper, a proposed antenna was designed with dimensions of 70 \(\times\) 31 \(\times\) 1.6 mm\({}^{3}\) by FR4 substrate which has good resistance. As compared with other models, which resonate at higher frequencies, the proposed model resonates at 0.915 GHz and 2.45 GHz. The resonating frequencies are in a lower band of frequencies, which are used for L and S band applications. This makes the proposed antenna highly effective for RFID and ISM band-based systems. Additionally, the proposed antenna provides 0.018 GHz and 0.13 GHz bandwidths for dual band frequencies.