## 1 Introduction  
Recently, the millimeter wave (mmWave) spectrum has become popular due to its applications in wireless power transfer, synthetic aperture radar imaging, satellite systems, and non-destructive testing [1, 2, 3]. So, the design of the antennas and beam-forming circuits at mmWave frequencies has also gained much interest. Techniques to miniaturize antennas have been used for a long time [4]. Most of the techniques fall into two categories: topology-based techniques and material-based miniaturization techniques. Techniques to minimize the size of the wide-band antenna were also reported in [4]. The antenna structures with large dimensions can be miniaturized by bending to form meander lines or broken into small segments using fractals. Even though engineering the ground planes helps reduce the size of the antenna, it also results in an increase in radiation on the back side. Periodic loading, which results in slow wave structures, can also be used to reduce the size of the antenna. Using high-dielectric substrates and superstrates and lowering the dielectric constant using perforation fall under material-based miniaturization. Using magnetodielectric substrates and using piezo electric materials also fall under this category [4]. CRLH concepts have been used in the design of leaky wave antennas and small resonant antennas [5]. The CRLH resonator has resonances in the left-handed region, the right-handed region, and the zero-order resonance. At zero-order resonance, the resonant frequency depends on the parameters of the CRLH resonator and not on the physical dimension of the CRLH resonator. So, a zero-order resonator (ZOR) can be designed at a frequency independent of its physical dimensions [5]. It is an important advantage compared to other miniaturization techniques. The miniaturization using metamaterial also comes under material-based miniaturization of the antennas [4]. The general structure of the CRLH resonator has a metallic via for achieving the left-handed inductance. The shape of the radiation pattern is mainly influenced by the position of the metallic via. So, even though CRLH resonators are smaller in size, the design of the antenna with patch-like radiation is difficult. Several techniques were used in the literature to obtain broad-side radiation using CRLH resonators at zero-order resonance, but monopole like radiation is more common. In [6], monopole-like radiation was achieved using a mushroom-like CRLH resonator and an inductor-loaded resonator. The metallic vias were at the center of the rectangular patch for the CRLH resonator and along the central axis for the inductor-loaded resonator. A patch-like radiation using the CRLH resonator at 4.88 GHz was reported in [7], where metallic-via were replaced by large patches. An eight-cell CRLH resonator arranged in a ring-like fashion with stubs connected at the center was used to design a dual-band antenna [8]. Since the stubs are connected at the center, metallic vias were avoided. Two semicircle patches with shorting pins at one corner formed a two-cell CRLH resonator in [9]. The radiation pattern achieved was patch-like, but if the position of the shorting pin was moved to the center of the semi-circle, monopole-like radiation could be obtained. Broadside radiation was achieved in [10] using a hybrid antenna consisting of a mushroom-type CRLH resonator imbedded inside a rectangular hole of a rectangular patch antenna. The antenna in [10] was fed using a circular patch with a coaxial probe. Via holes were connected to the patch antenna edges through switchable stubs [11] to obtain two types of radiation patterns. If the vias are connected to the patch antenna, negative permittivity is added, and a monopole-like radiation pattern is obtained at zero-order resonance. If the vias were not connected, the antenna in [11] would operate like a patch antenna. A monopolar radiation was obtained for the metamaterial antennas proposed in [12].