sensors Article
A Dual Band Frequency Reconfigurable Origami Magic Cube Antenna for Wireless Sensor Network Applications Syed Imran Hussain Shah and Sungjoon Lim *
ID
School of Electrical and Electronics Engineering, College of Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Korea;
[email protected] * Correspondence:
[email protected]; Tel.: +82-2-820-5827 Received: 2 September 2017; Accepted: 17 November 2017; Published: 20 November 2017
Abstract: In this paper, a novel dual band frequency reconfigurable antenna using an origami magic cube is proposed for wireless sensor network (WSN) applications. The proposed origami antenna consists of a meandered monopole folded onto three sides of the magic cube. A microstrip open-ended stub is loaded on the meandered monopole. The proposed origami magic cube can be mechanically folded and unfolded. The proposed antenna operates at 1.57 GHZ and 2.4 GHz in the folded state. In the unfolded state, the proposed antenna operates at 900 MHz and 2.3 GHz. The resonant frequency of the second band can be tunable by varying the length and position of the open stub. The origami magic cube is built on paper. Its performance is numerically and experimentally demonstrated from S-parameters and radiation patterns. The measured 10 dB impedance bandwidth of the proposed origami antenna is 18% (900–1120 MHz) and 15% (2.1–2.45 GHz) for the unfolded state and 20% (1.3–1.6 GHz) and 14% (2.3–2.5 GHz) for the folded state. The measured peak gain at 900 MHz and 2.3 GHz are 1.1 dBi and 2.32 dBi, respectively, in the unfolded state. The measured peak gain at 1.5 GHz and 2.4 GHz are 3.28 dBi and 1.98 dBi, respectively, in the folded state. Keywords: frequency switchable antenna; origami magic cube; meandered monopole; wireless sensor networks
1. Introduction During the last few decades, wireless communication has shown a tremendous growth. Many wireless applications have been integrated into a single radio device. For such radio devices, multiple antennas for various frequencies are not a suitable option because they would require a large amount of space with sufficient distance between the multiple antennas to avoid interference. Therefore, the antennas used in these radio devices should be multiband, wideband, or frequency reconfigurable. Compared to multiband and wideband antennas, a frequency reconfigurable antenna is an attractive choice because it can minimize the interference between multiple frequencies [1]. The monopole antennas have received great attention from last few decades because of its interesting features like omnidirectional radiation characteristics, compact size (λ/4), low cost, easy fabrication procedure and easy integration with other microwave circuits. Planar monopole antennas are mostly fed by microstrip line or coplanar waveguide. Due to its image in the ground plane, radiation pattern of the monopole antenna is similar to the dipole antenna. Dual band and multiband monopole antennas can play an important role in modern multiband communication systems. In [2], a compact monopole patch antenna with very interesting feature of wideband impedance bandwidth is presented. In [3], switching techniques for notched ultra-wide band monopole antenna is presented. In [4,5], a 3-dimensional (3-D) cubic antenna is presented for radio frequency identification (RFID) and wireless
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sensor networks (WSN). The antenna was fabricated on six planar sides of cube. The cube was realized by using flexible liquid crystal polymer (LCP) and paper which serve as substrate part of the antenna. Origami is a Japanese word composed of two terms Ori and Kami. Ori means folding and Kami means paper. Therefore, the word origami is used for paper folding [6]. It is an ancient art and has been used for various applications during the last few years [7]. Origami is attracting significant attention from researchers owing to its several advantages including deployability, easy fabrication procedure (folding), easy miniaturization, and a low fabrication cost. Recently, origami has been used for architecture and space-born applications as well as in various mechanical engineering designs [8,9]. The identified origami features are advantageous for antenna design applications where portability and deployability of the antenna is needed. Advancement in various simulation tools enables analysis and design techniques using the origami concept for antenna applications. Origami folding in one dimension, two dimensions, and three dimensions can be used to efficiently design an antenna that would not be possible by conventional antenna fabrication procedures [10,11]. A literature review reveals a few antennas that use the origami concept. For instance, in [12], a high-gain antenna was presented by using an origami tetrahedron structure. In [13], a deployable origami yagi antenna was presented but the antenna could be unfolded only by using a servo motor. A self-folding microstrip patch antenna was presented in [14]. A circularly polarized origami antenna was proposed for military field deployment [15]. In [16,17], a frequency reconfigurable origami antenna was presented. In this paper, a novel dual band frequency reconfigurable monopole antenna using an origami magic cube is proposed. The proposed origami antenna consists of an open-ended stub loaded meandered monopole designed on the magic cube. The proposed origami magic cube antenna can be folded and unfolded. The resonant frequencies for both bands are reconfigurable by folding and unfolding the magic cube. Therefore, the proposed antenna operates at 1.57 GHz and 2.4 GHz in the folded state. In the unfolded state, the proposed antenna operates at 900 MHz and 2.3 GHz. The measured 10 dB impedance bandwidth of the proposed origami antenna is 18% (900–1120 MHz) and 15% (2.1–2.45 GHz) for the unfolded state and 20% (1.3–1.6 GHz) and 14% (2.3–2.5 GHz) for the folded state. The measured peak gain at 900 MHz and 2.3 GHz are 1.1 dBi and 2.32 dBi, respectively, in the unfolded state. The measured peak gain at 1.57 GHz and 2.4 GHz are 3.28 dBi and 1.98 dBi, respectively, in the folded state. The origami magic cube is built on paper and, therefore, this is a low-cost antenna. The fabrication procedure for the antenna is very easy and fast. For outdoor WSN applications, the antenna must be stable and robust. Compared to the previous origami antennas such as [16,17], the proposed antenna is stable and robust. For instance, the origami antennas in [16,17] were made by folding a single sheet of paper. Thus, they are not very stable after repeated folding and unfolding. On the other hand, the proposed antenna is made by folding two paper sheets together and the magic cube geometry makes it robust in both the folded and unfolded state. The 3-D cubic shape is very suitable for WSN. The cubic shape allows for smart packing to easily integrate the sensor equipment [4]. Secondly, the proposed antenna provides quasi isotropic radiation pattern. Therefore, these two features (3-D cubic shape and its quasi isotropic radiation pattern) makes it suitable for wireless sensor networks. For example, the proposed antenna can be used in WSN for real time tracking and monitoring the environmental conditions. The proposed antenna can be instantly designed even without any EM simulator, by folding the two paper sheets in a magic cube shape and realizing a monopole of length (λ/4) for the desired frequency of operation. Therefore, it is very suitable for amateur radio for experimental purposes. On the other hand, the Internet-of-Things (IoT) is an emerging technology and it is estimated that 30 billion devices will be connected in 2020. Therefore, the low cost features and quasi isotropic radiation pattern of the proposed antenna make it a potential candidate for IoT applications. 2. Origami Magic Cube Antenna Design and Fabrication The presented antenna is designed on a paper substrate in an origami magic cube shape. The geometry of the proposed antenna in the folded and unfolded forms is presented in Figure 1. First,
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the origami magic cube is built and then the monopole is realized on the magic cube. The design Sensors 2017, 17, x FOR PEER REVIEW 3 of 8 procedure for the magic cube can be divided into several steps as shown in Figure 2. First, two different square papersquare sheetspaper withsheets the same (140 area mm(140 × 140 a thickness of 0.2ofmm are are selected. different witharea the same mmmm) × 140and mm) and a thickness 0.2 mm Sensors 2017, 17, x FOR PEER REVIEW 3 of 0 , BB0 , CC 0 ,8DD0 , FF0 , These sheets are labeled P-I and P-II. Sheet P-I is labeled with the segments AA selected. These sheets are labeled P-I and P-II. Sheet P-I is labeled with the segments AA′, BB′, CC′, 0 , MM0 , NN0 , PP0 , QQ0 , R and O as shown in Figure 2b. G and D. FF′, Sheet P-IID. ispaper marked segments DD′, Gsquare and Sheet P-IIwith iswith marked with LL segments LL′,×MM′, NN′,and PP′, QQ′, R and shown different sheets the same area (140 mm 140 mm) a thickness of O 0.2asmm are in selected. Theseand sheets are labeled P-I and P-II. Sheet P-I isAA’. labeled with the segments AA′, BB′, CC′, Sheet P-I isunfolded folded and unfolded across/along SheetFigure P-I is2b. folded across/along AA’. DD′, FF′, G and D. Sheet P-II is marked with segments LL′, MM′, NN′, PP′, QQ′, R and O as shown in Figure 2b. Sheet P-I is folded and unfolded across/along AA’.
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(a) (b) magic cube antenna in Figure 1. Proposed origami magic cube antenna (a) in the unfolded state (b)
Figure 1. Proposed origami magic cube antenna (a) in the unfolded state (b) magic cube antenna in theFigure folded1.state (L = 50 mm, L1magic = 24 mm, Lgantenna = 20 mm, = the 30 mm, L3 = Lstate 4 = 25(b) mm, L5 = cube 15 mm, W1 = 2inmm, Proposed (a)L2in unfolded magic antenna the folded state (L = 50origami mm, L1 = 24cube mm, Lg = 20 mm, L 2 = 30 mm, L3 = L4 = 25 mm, L5 = 15 mm, folded = state 25 mm). and theLfolded (L = 50 mm, L1 = 24 mm, Lg = 20 mm, L2 = 30 mm, L3 = L4 = 25 mm, L5 = 15 mm, W1 = 2 mm, W1 = 2 mm, and Lfolded = 25 mm). and Lfolded = 25 mm).
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Figure 2. Antenna fabrication steps: (a) selection of two paper sheets; (b) sheets marked with Figure 2. Antenna fabrication steps: (a) selection of paper two paper sheets; (b) sheets marked Figure 2. Antenna fabrication (a) selection of two sheets; (b) sheets with with alphabets; alphabets; (c) folding sheetsteps: P-I along AA’; (d) folding along CC’; (e) folding alongmarked BB’; (f) folding alphabets; (c) folding sheet P-I along AA’; (d) folding along CC’; (e) folding along BB’; (f) folding (c) folding along AA’; (d)(h)folding (e) sections; folding(i) along BB’; (f) folding along FF’; along sheet FF’; (g)P-I folding along EE’; dividingalong paperCC’; in three realization of the ground along FF’; folding along (h) dividing paper three sections; of plane; the (g) folding along EE’; (h) dividing inalong threeK’H; sections; (i) realization ofrealization the ground (j) folding plane; (j) (g) folding along H’H;EE’; (k)paper folding (l)in folding along KK’;(i) (m) folding along K’B;ground (n) plane; (j) folding along H’H; (k) folding along K’H; (l) folding along KK’; (m) folding along (n) sheet folded(k) paper sheet along P-II; (o)K’H; completed origami magic cube in folding unfoldedalong and folded states; (p) K’B; final along H’H; folding (l) folding along KK’; (m) K’B; (n) folded paper folded paper sheet P-II; (o) completed origami magic cube in unfolded and folded states; (p) final antenna prototype in unfolded folded states. P-II; (o) completed origami magicand cube in unfolded and folded states; (p) final antenna prototype in
antenna prototype in unfolded and folded states.
unfolded and folded states.
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This creates a crease which divides the paper into two triangular sections as shown in Figure 2c. Then, the paper is folded step by step along CC’, BB’, FF’, EE’ as shown in Figure 2d–g. These folding steps convert the paper into the hexagonal shape shown in Figure 2g. The hexagonal shaped paper consists of two longer sides BB’ and EE’ and four smaller sides AB, AE, A’B’, and A’E’. Next, the hexagonal shaped paper is divided into three sections. These sections consist of an upper section KK’EAB, a middle section HH’KK’, and a lower section HH’E’A’B’ as shown in Figure 2h. A copper 2017, 17, x FOR 4 of 8 strip with Sensors dimensions of PEER Lg ×REVIEW L is attached to the middle section (HH’KK’) of the hexagonal shaped paper to serve as the ground plane in the proposed antenna as shown in Figure 2i. In Figure 2j, This creates a crease which divides the paper into two triangular sections as shown in Figure 2c. the lower Then, section theishexagonal shaped paper, labeled asasHH’E’A’B, is folded towards the of paper folded step by step along CC’, BB’, FF’, EE’ shown in Figure 2d–g. These foldingthe middle section of steps the paper, labeled as HH’KK’. This folding converts the hexagonal shaped paper into a convert the paper into the hexagonal shape shown in Figure 2g. The hexagonal shaped paper consists of two longer sides BB’ and EE’ and four smaller sides AB, AE, A’B’, and A’E’. Next, the pentagonal shape. After this, section A’B’HE’ is folded towards HH’K’ and section K’KBAE is folded hexagonal shaped paper is divided into three sections. These sections consist of an upper section towards HH’KK’ as shown in Figure 2k–l. Next, section BAEK’ is folded towards section BKK’ to KK’EAB, a middle section HH’KK’, and a lower section HH’E’A’B’ as shown in Figure 2h. A copper convert it strip intowith a hexagonal shown tointhe Figure This hexagonal shaped paper dimensions shape of Lg × Las is attached middle2m. section (HH’KK’) of the hexagonal shaped has three sections. The section consists a square KK’HH’ and theintop consists of two tetrahedron paperbottom to serve as the ground plane of in the proposed antenna as shown Figure 2i. In Figure 2j, the lower section the hexagonal shaped labeled as HH’E’A’B, is folded middle sections K’KAH and of K’A’H’H. Then sheetpaper, P-II is chosen which has been towards labeledthe with sections LL0 , the HH’KK’. This folding converts the hexagonal shaped paper into a 0 , paper, MM0 , NN0section , PP0 , of QQ R, andlabeled O as as shown in Figure 2b. The folding steps mentioned for sheet P-I are pentagonal shape. After this, section A’B’HE’ is folded towards HH’K’ and section K’KBAE is folded repeated for sheet P-II to get another hexagonal shaped paper. finalsection folded shape towards HH’KK’ as shown in Figure 2k–l. Next, sectionfolded BAEK’ is foldedThe towards BKK’ to of sheet P-II is shown in Figure In the shape next step, the in folded P-Ihexagonal and P-IIshaped are joined convert it into a2n. hexagonal as shown Figuresheets 2m. This paper together has three to form a sections. The bottom section consists of a square KK’HH’ thedimensions top consists ofoftwo magic cube. The magic cube has six square-shaped sides.and The alltetrahedron sides are the same. sections K’KAH and K’A’H’H. Then sheet P-II is chosen which has been labeled with sections LL′, This magic cube can be folded and unfolded. The magic cube in the unfolded and folded states is MM′, NN′, PP′, QQ′, R, and O as shown in Figure 2b. The folding steps mentioned for sheet P-I are shown in repeated Figure for 2o.sheet After a magic cube, thefolded monopole is implemented three sides of P-IIbuilding to get another hexagonal shaped paper. The final folded shapeon of sheet the magic P-II cube. Copper film2n. having conductivity 4.4sheets × 105 and thickness ofto0.1 mm is used is shown in Figure In the next step, the folded P-IS/m and P-II areajoined together form a magic The magic cube six square-shaped sides. The dimensions of all sides the same.it does not for realization ofcube. the monopole. Ahas monopole antenna is realized by copper filmare because This magic cube can be folded and unfolded. The magic cube in the unfolded and folded states is crack for repeating folding and unfolding process. The final antenna prototype in unfolded and folded shown in Figure 2o. After building a magic cube, the monopole is implemented on three sides of the states are magic shown in Figure 2p. having The ANSYS High Structure (HFSS) cube. Copper film conductivity 4.4Frequency × 105 S/m and a thicknessSimulator of 0.1 mm is used foris used for electromagnetic simulation and A analysis ofantenna the proposed band switchable realization of the monopole. monopole is realized dual by copper filmfrequency because it does not crack antenna. for repeating folding andin unfolding process. Theantenna final antenna prototype in unfolded folded We used paper as a substrate our magic cube fabrication. Firstly, weand characterized the states are shown in Figure 2p. The ANSYS High Frequency Structure Simulator (HFSS) is used for paper by designing a T-resonator for our desired frequency range. In the desired frequency range (0 to electromagnetic simulation and analysis of the proposed dual band frequency switchable antenna. 3 GHz), the and in dielectric the paper waswe 2.2characterized and 0.04, respectively. Wedielectric used paperconstant as a substrate our magicloss cubetangent antenna of fabrication. Firstly, the A parametric study isaperformed to our determine the length of In the arm Lrange to get paper by designing T-resonator for desired frequency range. themonopole desired frequency (0 5 required 3 GHz), thefrequency dielectric constant and dielectric lossunfolded tangent of the paper 2.2 and 0.04, the desiredto resonant of 900 MHz in the state aswas presented in respectively. Figure 3a. When L5 A parametric study is performed to determine the length of the monopole arm L5 required to get is increased, the resonant frequency of the monopole decreases. In this study, L5 is chosen as 15 mm the desired resonant frequency of 900 MHz in the unfolded state as presented in Figure 3a. When L5 to get the isdesired operation frequency ofthe 900 MHz in the unfolded state. parametric is chosen as 15 mm study for increased, the resonant frequency of monopole decreases. In this study, L5 The various lengths (L1desired ) of the open stub of theofmonopole is presented in Figure 3b. Asstudy can be to get the operation frequency 900 MHz in the unfolded state. The parametric for seen from various lengths (L 1) of the open stub of the monopole is presented in Figure 3b. As can be seen from the S-parameters of the various lengths (L1 ) of the open stub, the resonant frequency of the second the S-parameters of the various lengths (L1) of the open stub, the resonant frequency of the second band can be easily controlled by varying the length of the open stub. In this study, L1 is chosen as band can be easily controlled by varying the length of the open stub. In this study, L1 is chosen as 24 24 mm to get operation frequency 2400 MHz. mm an to get an operation frequencyaround around 2400 MHz.
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Figure 3. Cont.
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Figure 3. Cont. Sensors 2017, 17, x FOR PEER REVIEW
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Figure 3. Cont.
(c) (c) Figure 3. (a)Figure Parametric study for L5for inLthe unfolded (b)parametric parametric study for length of(L the 3. (a) Parametric study 5 in the unfoldedstate; state; (b) study for length of the stub 1); stub (L1); Figure 3. (a) Parametric study forofLstub instub the state; (b) parametric study for length of the stub 5 of 2). (c) parametric study for position ).unfolded (c) parametric study for position (L2(L (L1 ); (c) parametric study for position of stub (L2 ). The position of the open-ended stub can also be varied to select the desired operation frequency
The position of the open-ended stub can also be varied to select the desired operation frequency as shown in Figure 3c. Based on this study, L2 is chosen as 30 mm in order to operate the antenna The position of3c. theBased open-ended canLalso be varied desired operation as shown in Figure on thisstub study, 2 is chosen as to 30 select mm inthe order to operate thefrequency antenna around 2400 MHz. as shown inMHz. Figure 3c. Based on this study, L2 is chosen as 30 mm in order to operate the antenna around 2400 3. Measurement Results around 2400 MHz. After the parametric study, the proposed antenna is fabricated with the optimal dimensions for 3. Measurement Results the required resonant frequencies. The antenna prototype is built on the origami magic cube and 3. Measurement Results After displayed the parametric proposed antenna fabricated with the of optimal dimensions for in Figurestudy, 2p in thethe unfolded and folded states.isThe reflection coefficients the antenna for Afterthe theresonant parametric study, theThe proposed antenna is fabricated with optimal dimensions for folded and frequencies. unfolded states are measured using an MS2038C vectoron network analyzer (Anritsu, the required antenna prototype is built thethe origami magic cube and Cary, NC, USA). The simulated and measured reflection coefficients of the proposed origami magic the required resonant frequencies. The prototype is built oncoefficients the origami cube and displayed in Figure 2p in the unfolded andantenna folded states. The reflection ofmagic the antenna for cube antenna are presented in Figure 4 for the folded and unfolded states. The proposed antenna displayed in Figure 2p in the unfolded and folded states. The reflection coefficients of the antenna for the folded operates and unfolded states measured using anInMS2038C vector analyzer at 1.57 GHz and are 2.4 GHz in the folded state. the unfolded state, network the proposed antenna (Anritsu, the folded and unfolded states are measured using an MS2038C vector network analyzer (Anritsu, Cary, NC, operates USA). The simulated measured reflection of the proposed origami magic at 900 MHz and and 2.3 GHz. The measured 10 dBcoefficients impedance bandwidth of the proposed Cary,antenna NC,origami USA). The simulated and measured reflection coefficients of the state proposed magic is 18%in (900–1120 MHz) (2.1–2.45 GHz) for the unfolded and 20%origami (1.3– antenna cube areantenna presented Figure 4 forand the15% folded and unfolded states. The proposed 1.6 GHz) and 14% (2.3–2.5 GHz) for the folded state. cube antenna are presented in Figure 4 for the folded and unfolded states. The proposed antenna operates at 1.57 GHz and 2.4 GHz in the folded state. In the unfolded state, the proposed antenna operatesat at 900 1.57MHz GHz and and 2.4 the measured folded state. In the unfoldedbandwidth state, the proposed antenna operates 2.3 GHz GHz.inThe 10 dB impedance of the proposed operatesantenna at 900 MHz and(900–1120 2.3 GHz. MHz) The measured dB impedance bandwidth of the proposed origami origami is 18% and 15%10 (2.1–2.45 GHz) for the unfolded state and 20% (1.3– antenna is 18% (900–1120 MHz) and 15% (2.1–2.45 GHz) for the unfolded state and 20% (1.3–1.6 GHz) 1.6 GHz) and 14% (2.3–2.5 GHz) for the folded state. and 14% (2.3–2.5 GHz) for the folded state.
Figure 4. Measured reflection coefficients of the proposed origami magic cube antenna in the folded and unfolded states.
Figure4.4.Measured Measuredreflection reflectioncoefficients coefficientsof ofthe theproposed proposedorigami origamimagic magiccube cubeantenna antennain inthe thefolded folded Figure and unfolded states. and unfolded states.
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Figure 5. Measured 3D radiation patterns of the proposed origami magic cube antenna in the
Figure 5. Measured 3D radiation patterns of the proposed origami magic (c) (d) cube antenna in the unfolded unfolded state (a,b): (a) at 900 MHz, (b) 2200 MHz; measured 3D radiation patterns of the proposed state (a,b): (a) at 900 MHz, (b) 2200 MHz; measured 3D radiation patterns of the proposed origami Figure 5.magic Measured 3D radiation patterns of (c,d): the proposed origami magic cube antenna in the origami cube antenna in the folded state (c) 1500 MHz, (d) 2400 MHz. magicunfolded cube antenna in the state (b) (c,d): (c)MHz; 1500measured MHz, (d)3D 2400 MHz. patterns of the proposed state (a,b): (a) folded at 900 MHz, 2200 radiation magic cube antenna in the folded state (c,d): (c) MHz, (d)chamber 2400 MHz.for all the operational Theorigami radiation pattern of the antenna is measured in 1500 an anechoic frequencies in the folded and unfolded states. In Figure 5, the measured 3D radiation of the The radiation pattern of the antenna is measured in an anechoic chamber for allpattern the operational The radiation pattern of the antenna is measured in an anechoic chamber for all theThe operational antenna is presented for the frequencies of 900 MHz and 2200 MHz in the unfolded state. antenna frequencies in the folded and unfolded states. In Figure 5, the measured 3D radiation pattern of the frequencies in the folded and of unfolded states. IndBi Figure 5, the measured 3D radiation pattern in of the the shows a measured 1.1 dBiofand at 900 MHz andin2200 respectively, antenna is presented forpeak the gain frequencies 9002.32 MHz and 2200 MHz the MHz, unfolded state. The antenna antenna is presented for the frequencies of 900 MHz and 2200 MHz in the unfolded state. The antenna unfolded state. Next, the proposed antenna is folded and the 3D radiation pattern of the antenna is shows a measured peak gain of of 1.11.1dBi and 2.32 dBi at 900 900MHz MHzand and 2200 MHz, respectively, in the shows a measured peakstate gainfor and 2.32 of dBi 2200The MHz, respectively, the measured in the folded thedBi frequencies 1.5atGHz and 2.4 GHz. antenna shows ainpeak unfolded state. Next, the proposed antenna is folded and the 3D radiation pattern of the antenna unfolded state. the dBi proposed is folded the 3D2.4 radiation pattern of the is gain of 3.28 dBi Next, and 1.98 for theantenna frequencies of 1.5and GHz and GHz, respectively, in antenna the folded is measured in the folded state for the frequencies of 1.5 GHz and 2.4 GHz. The antenna shows a measured in the folded state for the frequencies of 1.5 GHz and 2.4 GHz. The antenna shows a peak state. peak gain gainofof3.28 3.28dBi dBi and forfrequencies the frequencies of 1.5 GHz and 2.4 GHz, respectively, in the and 1.981.98 dBi dBi for the of 1.5 GHz and 2.4 GHz, respectively, in the folded state. folded state.
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Figure 6. Measured 2D normalized radiation patterns of the proposed origami magic cube antenna in (a) (b) (c) the unfolded state. (a) yz-plane, (b) xz-plane, (c) xy-plane. Figure 6. Measured 2D normalized radiation patterns of the proposed origami magic cube antenna in Figure 6. Measured 2D normalized radiation patterns of the proposed origami magic cube antenna in the unfolded state. (a) yz-plane, (b) xz-plane, (c) xy-plane.
the unfolded state. (a) yz-plane, (b) xz-plane, (c) xy-plane.
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radiation pattern pattern especially especially in in the the The measured radiation pattern provides quasi isotropic radiation unfolded state where gain deviation (difference between between maximum maximum and and minimum minimum of of gain) gain) is is even even less than 14 dBi. This feature makes it suitable for WSN applications. Gain Gain deviation deviation in in the the unfolded unfolded state is smaller because a meandered monopole monopole which which is is folded folded onto onto three three sides sides of of the the magic magic cube cube fully contributes in radiation. In the the folded folded state, state, some some portion portion of ofmeandered meandered monopole monopole is is overlapped overlapped resulting in reduced electrical length. Therefore, Therefore, in in the the folded folded state, state, gain gain deviation deviation is is more more than than the the unfolded state. In In Figure Figure 6, the measured normalized normalized radiation radiation pattern pattern of of the the antenna antenna is is shown shown for for the frequencies of 900 MHz and 2200 MHz in the the unfolded unfolded state. state. The The measured measured normalized normalized radiation radiation pattern is plotted forfor the the frequencies of 1500 MHzMHz and 2400 the folded pattern of ofthe theproposed proposedantenna antenna is plotted frequencies of 1500 and MHz 2400 in MHz in the state in Figure 7. In the folded state, the height of the antenna is reduced by 90%. folded state in Figure 7. In the folded state, the height of the antenna is reduced by 90%.
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Figure Figure 7. 7. Measured Measured 2D 2D normalized normalized radiation radiation patterns patterns of of the the proposed proposed origami origami magic magic cube cube antenna antenna in in the folded state. (a) yz-plane, (b) xz-plane, (c) xy plane. the folded state. (a) yz-plane, (b) xz-plane, (c) xy plane.
4. Conclusions 4. Conclusions A novel dual band frequency reconfigurable origami magic cube antenna was proposed. The A novel dual band frequency reconfigurable origami magic cube antenna was proposed. proposed origami antenna consists of a stub loaded microstrip fed meandered monopole. The The proposed origami antenna consists of a stub loaded microstrip fed meandered monopole. proposed origami magic cube antenna can be folded and unfolded to reconfigure the operating The proposed origami magic cube antenna can be folded and unfolded to reconfigure the operating frequencies. The proposed antenna operates at 1.57 GHz and 2.4 GHz in the folded state. In the frequencies. The proposed antenna operates at 1.57 GHz and 2.4 GHz in the folded state. In the unfolded state, the proposed antenna operates at 900 MHz and 2.3 GHz. The origami magic cube is unfolded state, the proposed antenna operates at 900 MHz and 2.3 GHz. The origami magic cube constructed out of paper and, therefore, this is a low-cost antenna. The fabrication procedure for the is constructed out of paper and, therefore, this is a low-cost antenna. The fabrication procedure for antenna is very easy and fast. The antenna is suitable for applications where portability and the antenna is very easy and fast. The antenna is suitable for applications where portability and deployability of the antenna is required. Therefore, the proposed antenna is a good candidate for the deployability of the antenna is required. Therefore, the proposed antenna is a good candidate for the internet of things (IoT), amateur radio, and WSN applications. In this work, we manually deformed internet of things (IoT), amateur radio, and WSN applications. In this work, we manually deformed the origami geometry without the actuator in order to demonstrate any feasibility. As a future work, the origami geometry without the actuator in order to demonstrate any feasibility. As a future work, we are going to integrate the proposed origami antenna with a pneumatic actuator. we are going to integrate the proposed origami antenna with a pneumatic actuator. Acknowledgments: This This research research was was supported supported by by the the MSIT MSIT (Ministry (Ministry of of Science Science and and ICT), ICT), Korea, Korea, under under the the Acknowledgments: ITRC (Information Technology Research Center) support program (IITP-2017-2012-0-00559) supervised by the ITRC (Information Technology Research Center) support program (IITP-2017-2012-0-00559) supervised by the IITP (Institute Information & Communications Technology Promotion) and the National (Instituteforfor Information & Communications Technology Promotion) and theResearch NationalFoundation Research of Korea (NRF) grant (NRF) fundedgrant by the Koreaby government (MSIP) (No. (MSIP) 2017R1A2B3003856). Foundation of Korea funded the Korea government (No.2017R1A2B3003856). Author analyzed, fabricated, fabricated, and and measured measured the the sample. sample. Author Contributions: Contributions: Syed Syed Imran Imran Hussain Hussain Shah Shah designed, designed, analyzed, Sungjoon Lim conceived the idea and advised regularly until the completion of the project. Sungjoon Lim conceived the idea and advised regularly until the completion of the project. Conflicts of Interest: The authors declare no conflict of interest. Conflicts of Interest: The authors declare no conflicts of interest.
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