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Despite widespread adoption of crowdfunding for funding social donation projects, its adoption among start-up entrepreneurs is significantly low, in developing countries in particular. Research has been performed to investigate the crowdfunding adoption intention of start-up entrepreneurs in Bangladesh. This study aimed to identify the motivation behind the intentions of the entrepreneurs to adopt crowdfunding, using the Unified Theory of Acceptance and Use of Technology (UTAUT) model with extensions. Empirical data were collected from 317 respondents and analyzed using Partial Least Squares-based Structural Equation Modeling (PLS-SEM). The results indicate that performance expectancy, effort expectancy, social influence, facilitating conditions and perceived trust mpact significantly ion the entrepreneurs’ behavioral intention to adopt crowdfunding. In contrast, trialability and perceived trust were not found to be significant determinants. However, trialability has a significant positive relation with use behavior or actual use, whereas no significant relationship has been identified between behavioral intention and use behavior.

A compact metamaterial inspired antenna operate at LTE, Bluetooth and WiMAX frequency band is introduced in this paper. For the lower band, the design utilizes an outer square metallic strip forcing the patch to radiate as an equivalent magnetic-current loop. For the upper band, another magnetic current loop is created by adding metamaterial structure near the feed line on the patch. The metamaterial inspired antenna dimension of 42 × 32 mm2 compatible to wireless devices. Finite integration technique based CST Microwave Studio simulator has been used to design and numerical investigation as well as lumped circuit model of the metamaterial antenna is explained with proper mathematical derivation. The achieved measured dual band operation of the conventional antenna are sequentially, 0.561~0.578 GHz, 2.346~2.906 GHz, and 2.91~3.49 GHz, whereas the metamaterial inspired antenna shows dual-band operation from 0.60~0.64 GHz, 2.67~3.40 GHz and 3.61~3.67 GHz, respectively. Therefore, the metamaterial antenna is applicable for LTE and WiMAX applications. Besides, the measured metamaterial antenna gains of 0.15~3.81 dBi and 3.47~3.75 dBi, respectively for the frequency band of 2.67~3.40 GHz and 3.61~3.67 GHz.

A planar, low-profile, dual-band and dual-polarized antenna on a semi-flex substrate is proposed in this paper. The antenna is fabricated on Rogers substrate with a thickness of 3.04 mm and sized at 70.4 × 76.14 × 3.11 mm 3 (0.37λ 0 × 0.40λ 0 × 0.016λ 0 ) only. The circular polarization property is enabled in the global navigation satellite system (GNSS) L1/E1 (lower) band by introducing a complementary split ring resonator on the antenna patch. Meanwhile, the antenna operates in the second (upper) 2.45 GHz WLAN band is enabled by etching a U-shaped slot on its ground plane. This simultaneous, dual-band and dual-polarized operation enables the proposed antenna to be applied in the indoor/outdoor wearable application. To isolate the antenna against the influence of the human body, a multiband artificial magnetic conductor (AMC) plane is added on the reverse side of the dual-band radiator. Comparison of the antenna without AMC in free space and when evaluated on the chest of a human body backed by AMC showed improved gain; from 3-5.1 dBi in the lower band, and from 1.53-5.03 dBi in the upper band. Besides that, the front-to-back ratio of the AMC backed monopole antenna also improved from 11-21.88 dB and from 2.5-24.5 dB in the GNSS and WLAN bands, respectively. Next, the specific absorption rate (SAR) of the monopole antenna with and without the AMC plane is assessed. Evaluation results indicate that the maximum SAR value decreased by up to 89.45 % in comparison with the antenna without AMC in the lower band. This indicates the effectiveness of the AMC array in increasing gain and FBR, besides reducing EM absorption in the human body.INDEX TERMS Wearable antennas, dual-band antennas, dual-polarized antennas, circularly polarized antennas, artificial magnetic conductor (AMC) plane.

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In this paper, a dual-band metamaterial absorber (MMA) ring with a mirror reflexed C-shape is introduced for X and Ku band sensing applications. The proposed metamaterial consists of two square ring resonators and a mirror reflexed C-shape, which reveals two distinctive absorption bands in the electromagnetic wave spectrum. The mechanism of the two-band absorber particularly demonstrates two resonance frequencies and absorption was analyzed using a quasi-TEM field distribution. The absorption can be tunable by changing the size of the metallic ring in the frequency spectrum. Design and analysis of the proposed meta-absorber was performed using the finite-integration technique (FIT)-based CST microwave studio simulation software. Two specific absorption peaks value of 99.6% and 99.14% are achieved at 13.78 GHz and 15.3 GHz, respectively. The absorption results have been measured and compared with computational results. The proposed dual-band absorber has potential applications in sensing techniques for satellite communication and radar systems.

A modified microstrip patch antenna is implemented on Polyethylene terephthalate (PET) substrate with a thickness of 0.125 mm for 5G applications. The wideband antenna of 60 375 mm 2 total dimensions is fabricated using novel inkjet printer and silver nano-particles as the conductive ink. The designed and fabricated antenna operates within 7 to 13 GHz and exhibits almost omnidirectional radiation pattern with an average gain of 5 dBi. The flexible antenna was also tested under bending conditions and showed good performance within the Xband region. The originality of the work lies in the combination of the antenna's structure, flexibility, and targeted frequency of operation.5G, flexible antenna, PET, wideband, X-band | I NT ROD UCTI ONWith the advent of 5G networks, a need to connect most devices and gadgets together and to the internet has become inevitable. The diversity in the interconnected devices rose the idea of designing flexible and robust antennas able to be mounted on curvy shaped or wearable devices. Such antennas must be able to be bent and deformed while maintaining good performance in terms of bandwidth, radiation patter, gain, and efficiency. The shift from rigid to flexible and bendable antennas imposes the employment and MPAs are a category of planar antennas which have been researched and developed extensively in the last three decades. They have been favored among antenna designers and have been used in many applications in wireless communication systems, both in the military and commercial sectors. These planar antennas have shown major advantages being low profile, planar, light, and easy to integrate with circuit elements. However, MPAs suffer from serious drawbacks including a very narrow bandwidth typically less than 5%, high feed network losses, high cross polarization, and low RF power handling capabilities due to the small separation between the radiating patch and its ground. 5,6,8 Therefore, many researches have been conducted on the conventional MPA to overcome the drawbacks mentioned earlier. For instance, the narrow bandwidth has been improved and increased in comparison with the conventional MPA by using different techniques such as truncated corners of the rectangular patch, 10,11 the employment of different substrate and conductive material with different thicknesses, and the use of partial ground as reported in many ultrawideband antennas. 4,6,10,[12][13][14][15][16] Because flexibility of antennas was not of a major concern until recently due to wearable devices and other medical applications, few are the works done on this field as compared to others. Therefore, in this project a flexible antenna targeting X-band frequencies is designed and fabricated by means of novel inkjet printing technology. The antenna's design in terms of operation, flexibility, size, materials, and technology used is one of its kind to our best knowledge and has yielded satisfactory results within the required specifications. | A NTEN NA DE S IG N AND C ONF I GU RATI ONThe proposed antenna i...