A compact planar UWB-MIMO antenna array with WLAN band rejection is presented. The array consists of four monopole radiators and a common ground plane. These monopoles are placed in such a way that the polarisation diversity of nearly placed radiators is exploited, resulting in high isolation. The proposed MIMO antenna array is electrically small (50 × 39.8 mm 2), printed on a low loss 1.524 mm thick Rogers TMM4 laminate with a dielectric constant of 4.5 and a loss tangent of 0.002. A band-stop design was inserted on the ground plane to behave similar to a LC band-stop filter and reject the WLAN band. Simulation and measurement results satisfy the return loss requirement of better than 10 dB and isolation better than 17 dB over the entire 2.7-5.1 and 5.9-12 GHz bandwidths.

A new compact multiple-input multiple-output (MIMO) ultra-wideband (UWB) antenna array is presented. The antenna array initially consisted of two monopoles placed side by side at a distance of 4 mm. A strong mutual coupling was observed so the design was modified by rotating the second radiator at 90° at a distance of 1 mm. Wideband isolation is achieved by exploiting polarisation diversity of antenna elements. Simulation in HFSS and printed prototype results validate the high isolation, over 21 dB on the entire 2.5-12 GHz frequency range. A prototype was fabricated on a low loss substrate of Rogers TMM4 measuring 23 × 39.8 mm2. To evaluate the diversity performance, the envelope correlation coefficient was calculated resulting below -20 dB, thus ensuring good diversity performance. The compactness of the proposed UWB-MIMO design is finally compared against alternative solutions already present in the literature

A Multiple‐input multiple‐output antenna array with two radiating elements having a wide bandwidth is reported in this work. Spatial diversity has been introduced to achieve the diversity gain and the array was kept compact by introducing five parasitic decoupling elements on the bottom of the substrate; each having a length equal to λ/2 at a specific frequency. Each resonant element offers a resonant bandwidth of 1 GHz starting from 3 GHz to 8.5 GHz. Good agreement between the measured and simulated results shows that the antenna system performs very well over the frequency range 3 GHz to 8.5 GHz. In addition, an isolation of more than 15 dB is achieved with the help of the parasitic elements, while keeping an edge‐to‐edge and center‐to‐center separation of 4 mm and 19 mm, respectively. The proposed antenna measures 26 × 40.5 mm2, and it is suitable for handheld devices, personal digital assistants, next generation home entertainment systems, and robots. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1677–1682, 2015

Presented are two different frequency reconfigurable ultra-wideband multiple-input multiple-output (MIMO) antenna array designs capable of rejecting on-demand all WLAN communications in the 4.8 to 6.2 GHz range. Both arrays consist of two monopole UWB radiators placed orthogonally with respect to each other to introduce polarisation diversity and a quarter-wave stub connected to the ground plane via pin diodes is used to introduce the on-demand band rejection feature. One array design has separate ground planes and the other has two ground planes connected with a printed conductor (i.e. shared). For both cases, an isolation better than 20 dB between the elements is achieved in the 2 to 12 GHz frequency range with simulations and a manufactured prototype.

In this article, a novel design of a compact planar Ultra Wideband (UWB) monopole antenna with dual band notched characteristics has been presented. The antenna has a unique structure meeting UWB standards. The proposed antenna is fed through a 50 normalΩ micro strip feed line, whereas a better impedance is achieved by truncating the ground plane. The dual notches are achieved by incorporating a meandered slot on the radiator patch and U‐slot in the feed line. The antenna is fabricated on FR‐ 4 substrate having a compact size of  33 × 32 × 1.5 normalmnormalm3. A good agreement is observed between measured and simulated results. The radiation pattern is omnidirectional in H‐plane, whereas dipole like radiation pattern is observed in the E‐plane. The gain of antenna is stable across the whole UWB except at notched bands. It is shown that any UWB can be notched at any desired frequency band by incorporating appropriate slot length.

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In this article, an antenna with two patch elements is pattern and frequency reconfigured. One feed line is used to excite the two patch elements placed at any angle with respect to each other. The maximum rotation of each patch antenna element incorporated is 458. For the impedance matching with 50 X, both elements are fed from the corner. The radiating elements are fed simultaneously using one feed line with the help of PIN diodes. When patch 1 is excited by biasing PIN diode 1, a broad side radiation pattern in the yz plane of the patch 1 is observed. Therefore, for the rotation angle by 7.58 the pattern rotation is about 58 Similarly, biasing PIN diode 2, resulted excitation of Patch 2. It is observed that pattern reconfiguration of 308 can be achieved by biasing PIN diode 1, whereas, up to 2308 pattern reconfiguration can be achieved by exciting PIN diode 2, without compromising on the gain of the radiating elements. On the other hand, to achieve the frequency reconfiguration, two small radiating patches are added at 0.7 mm gap with the large radiating elements. PIN diodes are used between the small and large radiating elements. When diodes on the antenna elements are