Compact UWB MIMO antenna with cross‐shaped unconnected ground stub using characteristic mode analysis

Abstract

In this letter, a compact ultrawideband (UWB) multi‐input‐multi‐output (MIMO) antenna with cross‐shaped unconnected Ground stub using characteristic mode analysis (CMA) is presented. The proposed work consists of two elliptical shape monopole UWB antenna with a cross‐shaped stub in the ground plane. The compact MIMO antenna has the dimension of 25 × 25 × 1.6 mm3. These monopoles are able to excite several characteristic modes (CMs), which support to wideband resonance, and cross‐shaped stub support CM at lower frequency band in the ground plane and reduces mutual coupling between monopoles. The UWB MIMO antenna is resonating in frequency bands from 2.97 to 13.8 GHz bandwidth with a good mutual coupling (<−15 dB). The diversity performance envelop correlation coefficient (ECC) and diversity gain (DG) of the antenna are less than 0.05 and more than 9.97, respectively. The experimental result confirming a good treaty with the simulated ones, so that the proposed antenna is suitable for compact UWB MIMO applications.

A Review on Different Techniques of Mutual Coupling Reduction Between Elements of Any MIMO Antenna. Part 1: DGSs and Parasitic Structures

“…Along with a slit on the shared circular‐shaped radiator, an inverted Y‐shaped stub has been introduced in the ground plane at an angle of 45° (Srivastava & Kanuijia, 2015) to minimize the MC. Because of instrumental contributions of protruding ground stub structures in reducing MC particularly among wideband and UWB‐MIMO antenna elements many such designs have been introduced, among those some popular designs are folded Y‐shaped (Khan et al., 2015), diagonally integrated strip (Chacko et al., 2013; Gao et al., 2014), extended rectangular stub (Yoon et al., 2011), protruded I‐shaped stub at an angle of 45° (Zhu et al., 2016), an inverted pair of L‐shaped strips (Chandel et al., 2018; Khan et al., 2017a), an inverted L‐shaped strip (Kumar et al., 2019b), tree‐like stub (Zhang et al., 2009) as represented in Figure 14a, arrowhead‐shaped stub at an angle of 45° (Zhu et al., 2016), an inverted L‐shaped and I‐shaped stub (Liu et al., 2013) as represented in Figure 14b, funnel‐shaped stub (Gautam et al., 2018), circular arcs shaped stubs (Mathur & Dwari, 2018b), extended curved stub (Biswal & Das, 2019), partial ground T‐shaped stub (Malviya et al., 2016a), inverted L‐shaped stub integrated with T‐shaped slot (Singh et al., 2013), etching T‐shaped slot on the radiator and extended arrow‐shaped stub (Mao & Chu, 2014), pair of extended I‐shaped (Sharawi et al., 2011), a rectangular slot with one circular end embedded with two inverted‐L‐shaped branches (Shoaib et al., 2014), a cross‐shaped stub (Singh & Tripathi, 2019), F‐shaped stubs (Iqbal et al., 2017), a dual‐inverted‐L‐shaped ground branch with a slot (Zeng et al., 2012), two protruded ground parts (Li et al., 2013), a stepped stub at an angle of 45° (Biswal & Das, 2018a), two inverted L‐shaped and one I‐shaped stub (Hong et al., 2008), a pair of L‐stubs, spiral stubs, and L‐slots (Huang et al., 2015a), narrow metallic and slot stubs (Krishna & Kumar, 2016), grounded stub along with two F‐dual grounded circular ring resonator (Mathur & Dwari, 2019a) as represented in Figure 15a, two F‐shaped stub and rectangular slots (Wani & Vishwakarma, 2016) as described in Figure 15b, a simple I‐shaped stub (Mchbal et al., 2018), a rectangular vertical arm (Saxena et al., 2017), inverted L...…”

A Novel Two Ports MIMO Antenna Having Dual Stopped-band Functionality and Enhanced Isolation

“…The 3.5 GHz centered notched band is obtained by etching slots in the radiators. In article [12], a 25×25 mm 2 dimension UWB antenna operating in 2.97-13.8 GHz bandwidth is fabricated. A cross-shaped un-connected ground stub is proposed to enhance isolation.…”

Mutual Coupling Reduction Using Ground Stub and EBG in a Compact Wideband MIMO-Antenna

“…The resulting multi-period EBG structure made by this method will remain uni-planer and thus attract filter designers [16]. Another small size UWB MIMO antenna with the dimensions of 25 × 25 ×1.6 mm 3 , having cross shaped isolated ground stub and operating in 2.97-13.8GHz frequency band, is presented in [17]. The antenna has a high isolation (S21< -15 dB), low ECC (< 0.05) and a high diversity gain (DG > 9.97).…”