## 1 Introduction  
The communication industry today requires miniaturised, compact antennas with enhanced bandwidth for developing smaller and high-speed communication systems. Miniaturisation of antennas can be achieved by converting conventional antenna designs into electrically small antennas (ESAs). One of the most commonly used conventional types of antenna is microstrip patches because of their advantages such as ease of fabrication, simple design, low cost, etc. However, they have radiating patch size much larger than the dimensions required for components that can be accommodated in modern compact devices. This paper focuses on the conversion of a conventional circular patch into an electrically small antenna with dual-band and enhanced bandwidth using metamaterial loading. ESAs are antennas having certain defining electrical parameters proposed by [PERSON] and then by [PERSON] [1]. These parameters are derived mathematically from wave number \({}^{\prime}K=2\pi/\lambda_{0}\) and spherical radius around the highest dimension of the unit cell '\(a^{\prime}\). Based on these values ESAAs are defined using the mathematical formula \(ka<1\). Antenna designers find attractive features of ESAAs--such as compactness of size, simplicity of structure, etc.--useful for developing compact antennas for modern applications [2, 3, 4]. ESAAs also have certain disadvantages such as high reactance and low radiation resistance due to their small electrical size which in turn results in high quality factor (\(Q\)). In ESAs decrease of the value of electrical size '_ka_' closely correspond to the decrease of parameters such as bandwidth, efficiency, and gain [1]. Use of defected ground structures [5; 6] and metamaterials (MTMs) [7; 8] are the two most commonly used methods for developing ESAs from conventional antennas. MTMs are practically developed by [PERSON] et al. [9], and their unique properties attract antenna designers, who incorporate them in existing antennas for performance enhancement [10; 11]. MTMs are artificial electromagnetic structures with unusual properties and can be classified into mu-negative (MNG) MTM (\(\mu<0\)), epsilon-negative (ENG) MTM (\(\varepsilon<0\)) [12; 13], and double negative (DNG) MTM (\(\mu<0\) and \(\varepsilon<0\)) [12; 14]. The most commonly used MNG-MTMs are split ring resonators (SRRs) whereas the complementary split-ring resonators (CSRRs) belong to ENG-MTMs [13]. [PERSON] and [PERSON] developed the concept of electrically small MTM inspired antennas [15]. In this antenna, an MTM unit-cell has been placed in the vicinity of the driven element, thereby utilizing its features for enhancing the properties of the driven element. As a result, the impedance matching and overall radiation efficiency of the antenna are improved without using additional matching networks. [PERSON] et al. used the MTM unit-cell as a parasitic element in the near-field of the driven element and it has become the dominant radiating component of the overall system at the desired resonant frequency [16]. Even though SRRs are generally used for the design of MTM inspired antennas with miniaturised size [15; 16; 17], CSRRs are loaded in patch antennas for their size reduction [18; 19; 20; 21; 22; 23; 24; 25; 26; 27] because they can be easily integrated in the ground plane of the antenna without altering the radiating patch. [PERSON] et al. successfully generated a metamaterial effect by etching CSRR in the ground plane of a circular microstrip patch antenna [18]. Compared with the conventional circular patch antenna, the effective footprint area of the antenna using CSRR as a defected ground plane, is reduced approximately by 64%. By introducing single complementary split ring in the ground plane, dual band resonance and miniaturisation have been achieved [19] and the antenna achieves about 70% reduction in the resonant frequency and 89% reduction in the radiating patch size when compared with the conventional microstrip antenna.