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This manuscript introduces a novel miniaturized super wideband (SWB) hexagonal fractal spatial diversity 2-element multiple-input-multiple-output (MIMO) antenna for broadband applications, as a compact wideband antenna is required for military radio and space communication devices. The designed antenna includes two hexagonal (1 st modified Koch iteration) Koch fractal radiators with two linear tapered feedlines (TLTF) and a step tapered slotted ground plane (STSGP) that provides the broad impedance characteristic with miniaturized size in the operating band of 1.78-30 GHz. Moreover, the STSGP is also accountable for enabling the isolation (S 12/21 ) better than 10 dB. To further meet the isolation higher than 22 dB, a meander line is protruded from the ground plane while maintaining a 6 mm edge-to-edge distance between two antenna elements. Typically, the MIMO antenna with high isolation is beneficial for highspeed data transmission. The experimental outcomes represent that the proposed MIMO antenna is with the advantages of reasonably good diversity gain (nearly 10 dB), stable radiation patterns, high peak gain (almost 6.6 dBi), and moderate radiation efficiency (around 85%) across -10 dB impedance bandwidth. The total active reflection coefficient (TARC) and envelop correlation coefficient (ECC) are less than -25 dB and 0.1 respectively. Due to all these attributes, the proposed 2-element MIMO antenna array can be a potential candidate for military radio, spectrum sensing for cognitive radio, and space communication applications.

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In this article, a compact super wideband (SWB) monopole antenna with a wide-frequency is designed and analyzed for future handheld gadgets. The designed antenna is made by etching four slots on a round cornered rectangular patch which are connected through a 50-Ω triangular tapered microstrip transmission feedline (TTMTF) for broadband impedance matching. A triangular slot is etched on the semicircular partial ground plane, which helps to shift the lower frequency edge of 1.07 GHz to 1 GHz. The experimental results show that the proposed antenna operates over a wide frequency range of 1-30 GHz with a reflection coefficient of less than −10 dB. The antenna acquires a compact dimension of 25 × 16 × 0.787 mm 3. Further, an equivalent circuit method is used to analyze the proposed structure, and its outcome is compared with the simulated and experimental results. The peak gain of the designed antenna is about 5.5 dBi. The proposed antenna has low cross-polarization even at higher frequencies. Finally, the time domain analysis is also carried out to see the distortion between transmitting and receiving modes. The designed antenna can be used for various wireless applications such as NB-IoT, GPS, Wi-BRO, ISM band, IRNSS, WiMAX, X-band, Ku-band, and K-band.