Miniaturized frequency reconfigurable pentagonal MIMO slot antenna for interweave CR applications

Abstract

In this article, a miniaturized 4‐element frequency reconfigurable multiple‐input‐multiple‐output (MIMO) antenna system is presented. The proposed design is low profile with planar configuration. The design consists of pentagonal slot‐based frequency reconfigurable antenna elements. Varactor diodes are used to change the capacitive reactance of the slot. The MIMO antenna system can be tuned over a frequency band covering 3.2 to 3.9 GHz with at least 100 MHz bandwidth within each band. The proposed antenna covers several commercial standards including WiMAX (3.4‐3.6 GHz), TDD LTE (3.6‐3.8 GHz), and Wi‐Fi 802.11y (3.65‐3.7 GHz), along with several other bands. The proposed design was realized on a board of dimensions 60 × 120 mm2. The isolation between adjacent antenna elements is improved using slot‐line based defected ground structures (DGS). The antenna maintains a minimum isolation of 10 dB in its entire covered operating bands. The antenna is also analyzed for its far‐field characteristics and MIMO performance parameters. The proposed design is suitable to be used in mobile handsets for cognitive radio (CR) platforms.

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

“…Along with the neutralization line, four slits have been etched in the ground (Yang et al., 2016) to reduce MC between the elements of the multiband MIMO antenna working for GSM, DCS, and long term evolution (LTE) indoor applications. Two slots (Addaci et al., 2014), a wide slot and a pair of narrow slots (Nandi & Mohan, 2017) as represented in Figure 9a, six slits (Jaglan et al., 2017, 2018), simple wide slot (Ouyang et al., 2011), a vertical slot along with T‐shaped ground stub (Liu et al., 2015) as represented in Figure 9b, inverted T‐shaped slot along with a capacitor (Park et al., 2012), one T‐shaped slot and two‐stepped slots (Jetti & Nandanavanam, 2018) as described in Figure 10a, a narrow slot (Ren et al., 2014) as represented in Figure 10b, slitted pattern (Chiu et al., 2007), two symmetric stepped “L”‐shaped open ground slots (Biswal & Das, 2018b), T‐shaped slot impedance transformer (Zhang et al., 2012), two λ /4 slots (Zuo et al., 2010), E‐shaped slot on the radiator and narrow ground slot (Bhanumathi & Sivaranjani, 2019), slot line based DGS (Hussain et al., 2019), six pair of slits (Wu & Chu, 2014), n shaped slot etched below the feed‐line (Ul Haq & Koziel, 2018), meandered slot (Ayatollahi et al., 2012), L‐shaped slot (Huang et al., 2015a), series of slits (Li et al., 2009), four slots etched (Ikram et al., 2018), H‐shaped slot (Kang et al., 2016), as represented in Figure 11a, quasi‐cross‐shaped slot (Lu et al., 2011), two T‐slots, and a rectangular slot (Marzudi et al., 2015), as described in Figure 11b, triangular slots and meshed metal strip (Nirmal et al., 2019), again a pair of slits (Sharawi et al., 2012), two λ /2 slots (Sonkki & Salonen, 2010), cross‐shaped slot and a sickle‐shaped metallic strip (Srivastava & Mohan, 2015), two U‐shaped slots (Zhou et al., 2012) as represented in Figure 12a, two asymmetric dumbbells shaped slot, and one decoupling slot (Yang et al., 2018) as depicted in Figure 12b while a P‐shaped slot and two F‐shaped strips (Zhai et al., 2013) have been inserted in the ground p...…”

An integrated antenna for cognitive radio wireless sensor networks and HD video transmission applications

“…MIMO technology is solving the multi‐path fading and increasing the system's channel capacity without using the additional spectrum and power. Furthermore, UWB MIMO, 3‐6 UWB antenna with band notch characteristics, 7‐10 Re‐configurable CR antenna, 11‐16 and integrated CR antennas 17‐19 have been reported in the literature. Most of the reported designs in the literature for CR applications use independent 17‐19 and re‐configurable UWB / NB antennas for detection and communication 11‐16 .…”

“…Furthermore, UWB MIMO, 3‐6 UWB antenna with band notch characteristics, 7‐10 Re‐configurable CR antenna, 11‐16 and integrated CR antennas 17‐19 have been reported in the literature. Most of the reported designs in the literature for CR applications use independent 17‐19 and re‐configurable UWB / NB antennas for detection and communication 11‐16 . However, re‐configurable antennas have the following disadvantages: (i) The design of the biasing circuit is complicated, the switching is affected by non‐linearity, and the PIN diode requires additional power 11‐16 .…”

Compact planar frequency reconfigurable multiple‐input‐multiple‐output antenna with pattern and polarization diversity characteristics for WiFi and WiMAX standards

“…On the other hand, several frequency reconfigurable MIMO antenna designs have been reported in the literature. 4,[26][27][28][29][31][32][33][34] However, most of these frequency reconfigurable MIMO antenna designs are large in size, which makes them unsuitable for compact portable devices. Moreover, none of the existing frequency reconfigurable MIMO antenna designs show compact size and high isolation with pattern and polarization diversity characteristics altogether in dual bands.…”

“…On the other hand, several frequency reconfigurable MIMO antenna designs have been reported in the literature . However, most of these frequency reconfigurable MIMO antenna designs are large in size, which makes them unsuitable for compact portable devices.…”