2180
|
KHAN
Received: 1 February 2017 DOI: 10.1002/mop.30709
Pattern and frequency reconfiguration of patch antenna using PIN diodes Muhammad Saeed Khan1
|
ET AL.
biased, patches resonate at 2.43 GHz otherwise the resonance occurred at 3.3 GHz. For the comparison with simulation results, a prototype is fabricated on low loss 1.524 mm thick Rogers TMM4 laminate (Er 5 4.5, tand 5 0.002). In the fabricated prototype, both the radiating elements are rotated at maximum angle and results are compared. A good agreement at both frequencies and radiation pattern reconfiguration is observed. The gain is almost 5.5 dBi for the reconfigured patterns at 3.3 GHz and 4.9 dBi at 2.43 GHZ. The antenna has maximum dimension of 58 3 100 mm2.
Adnan Iftikhar2 | Antonio-Daniele Capobianco1 |
KEYWORDS
frequency reconfigurable, patch antenna, pattern reconfiguration
Raed M. Shubair3 | Bilal Ijaz2 1
Dipartimento di Ingegneria dell’Informazione, University of Padova, Via Gradenigo 6/b, Padova 35131, Italy 2
Electrical Engineering Department, COMSATS Institute of Information Technology, Islamabad Campus, Islamabad, Pakistan 3
Electrical and Computer Engineering Department at Khalifa University, UAE and Research Laboratory of Electronics of Massachusetts Institute of Technology (MIT), Massachusetts Correspondence Muhammad Saeed Khan, Dipartimento di Ingegneria dell’Informazione, University of Padova Via Gradenigo 6/b, 35131 Padova, Italy. Email:
[email protected]
Abstract 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
1 | INTRODUCTION The advancement of modern wireless communication systems requires the combination of multiple applications into a single device. For this purpose, either multiple antennas can be integrated inside the device or a single antenna with multiple functionalities can be unified in the system. Thus, one of the possible ways to achieve multiple functionalities of an antenna system is the reconfiguration in terms of frequency, radiation, or space. Microstrip patch antennas because of their robustness and efficiency have been used in modern communication systems. Therefore, reconfiguration capability of the patch antenna can add multiple dimensionalities to any system. In the past, different methods have been employed to achieve multiple functionalities of a single patch. Depending on the system requirement, the reconfigurable antenna can switch between polarizations,1 radiation patterns,2–4 frequencies,5–7 or combination of any of these properties.8 Several reconfigurable techniques have been proposed since the rise of reconfigurable antenna. These techniques are categorized in four major techniques such as electrical, mechanical, optical, and material change.8 Switches are used to connect and disconnect the antenna parts for electrical reconfiguration. These connections redistribute the antennas currents resulting in the alteration of their properties. Radio frequency micro-electromechanical systems (RFMEMS),9 PIN diodes,10 or varactors11 are used for electrical reconfiguration. In Ref. [1], a lot loaded Yagi patch antenna was proposed for dual band pattern reconfiguration. The reconfigurability was achieved by changing the state of the switches in the slots. The parasitic patches were placed on the both sides of
KHAN
|
ET AL.
F I G U R E 1 Layout of the proposed antenna. Optimized dimensions in mm are: ws 100, ls 5 58, wp 5 30, lp1 5 36, lp2 5 41, wf 5 2.26, lf 5 15. [Color figure can be viewed at wileyonlinelibrary.com]
2181
patch 2, when these patched were rotated 458 from the center. For frequency reconfiguration, diodes are used on the patches while for pattern reconfiguration, each patch is connected to feed line by activating the specific diode and rotated at an angle up to maximum rotation of 458. The proposed antenna has a simple structure 58 3 100 mm2, easy to manufacture and good far-field characteristics which makes if efficient solution for the devices where the frequency reconfiguration and pattern reconfiguration is required simultaneously. Moreover, the concept of rotating patch antennas and use of one feed line showed that frequency and pattern reconfiguration can be achieved simultaneously.
2 | ANTENNA DESIGN
the driven patch and slots were etched inside the parasitic elements. In Ref. [2], a series fed array was connected to reconfigure the frequency of array and realize broad side radiation pattern. The array was fed with Composite Right and Left Hand Transmission Lines (CRLH-TLs). The reconfigurability was achieved from 2.43 to 1.97 GHz. Another work was reported in Refs. [3,12] and by using the stubs on the ground plane to reject the WLAN. The work presented in the literature showed that most of the research is performed on achieving the reconfiguration either in terms of frequency or radiation pattern. However, designs capable of having the liberty of reconfiguring frequency and radiation pattern at the same time are not being explored or limited. In this article, a complete design shown in Figure 1, capable of switching between frequency and radiation pattern is proposed. A single feed antenna is proposed which can be switched between frequencies and patterns. The radiating elements are connected using a single feed line with the help of diodes. Whereas, the radiation pattern reconfiguration of the two patches on the left and right of the broad side is achieved by rotating the patch. The pattern was reconfigured at 308 to the right side of the yz-plane by activating patch 1 and at 2308 to the left side of the yz-plane by activating
The final layout of the proposed antenna is depicted in Figure 1. Initially, a simple rectangular patch with length lp2 was designed to resonate at 2.43 GHz. The patch was fed from the one end so that its duplicate can be placed and fed from the corner. The corner fed technique was adopted to achieve the maximum angle of rotation of the patches. The second patch was then placed at the edge of the feed line as shown in Figure 1. The feed line was designed for 50 X impedance having width of 2.26 mm. The designing of the layout shown in Figure 1 and simulations were performed in Full wave 3D electromagnetic software High Frequency Simulation Software (HFSS).13 Diodes were used to connect the patches with the feed line, when diode 1 is activated, patch 1 resonated. Whereas, biasing of diode 2 resulted resonance of the patch 2. To achieve the frequency reconfigurations of the patch antennas, a small strip of length 4.3 (lp2 2 lp1 20.7 mm) was introduced on both the patches. Initially, length of the patches was lp1 (36 mm) and patches resonated at 3.3 GHz. This resonance occurred because of the shorter electrical length of the patch antennas. When small strips of length 4.3 mm were introduced, separated at a distance of 0.7 mm, PIN diodes were incorporated, and biased; the patches
FIGURE 2
FIGURE 3
Magnitude of simulated reflection coefficient when PIN diode 1 is biased and PIN diodes on patch 1 are biased and unbiased
Magnitude of simulated reflection coefficient when PIN diode 2 is biased and PIN diodes on patch 2 are biased and unbiased
2182
|
FIGURE 4
KHAN
ET AL.
Radiation patterns in xz plane at 2.43 GHz, when patches are rotated with 158 step: (A) when diode 1 is biased, (B) when diode 2 is biased
resonated at lower frequency of 2.43 GHz. For the continuation of RF current in the small strip, 3 PIN diodes were used between the large patch (lp1) and small strip. A small copper strip with the RLC boundary setup was used in the simulation environment to represent the equivalent circuit of PIN diodes3 and realization of PIN diodes. The switching between the bands is shown in Figures 2 and 3 when diode 1 and diode 2 was biased, respectively. Furthermore, to achieve the radiation pattern reconfiguration, the patches are rotated at an angle with a shift of 7.58 with respect to the orientation of the feed line. The direction of the rotation of patch 1 is shown in Figure 1 with the angle u. Patch 1 was rotated clockwise with respect to the direction normal to the x-axis. The angle of 7.58 was investigated after a detailed parametric simulation of the angle and observation of the simulated radiation pattern. Similarly, to achieve the radiation pattern reconfiguration on the anticlock wise direction, patch 2 was rotated at an angular shift of 7.58 in the
anticlock wise direction. 2u symbol in Figure 1 shows the direction of rotation of patch 2.
F I G U R E 5 Photograph of the fabricated prototype which diodes and chokes. [Color figure can be viewed at wileyonlinelibrary.com]
F I G U R E 6 Simulated and measured |S11| of the final design. [Color figure can be viewed at wileyonlinelibrary.com]
3 | EFFECT IF PATCH ROTATION ON RADIATION PATTERN Finally, for the pattern reconfiguration of the patch antennas, radiating elements are rotated simultaneously. The rotation of patches in clockwise and anti-clockwise direction resulted in reconfiguration of antenna radiation pattern. Both patches were first placed on their initial position as shown in dotted lines in Figure 1. Then each patch was rotated simultaneously at a step angle of 7.58. When patch 1 was rotated anticlockwise with an increment of 7.58, its pattern started to shift 58 in the xz-plane. When the patch 1 was rotated 458, the radiation pattern was shifted 308. The radiation pattern of the patch 2 was shifted in clock wise with angular shift of
KHAN
|
ET AL.
FIGURE 7
Measured radiation patterns when patches are resonating at 2.43 GHz. (A) PIN diode 1 is biased, and (B) PIN diode 2 is biased
7.58, a similar fashion of radiation pattern with phase shift of 58 was observed in u direction (clockwise direction). The shifts in the radiation patterns of patches 1 and 2 are depicted in Figure 4. A radiation pattern shift of 108 by activating and angular variation of 158 is shown in Figure 4A, whereas Figure 8B shows the pattern variation of patch 2 in the anticlockwise direction. It was observed that when diode 1 was biased and all diodes on patch 1 were activated to connect small strip and larger patch: Patch 1 resonated at 2.43 GHz. However, with the same configuration and at an angular shift of 08, radiation pattern of patch 1 in xz plane was in broadside direction with 08 phase. This is shown with solid black line in Figure 8A. It was observed from the step by step angular shift increment of 7.58, the radiation pattern phase
FIGURE 8
2183
increment was addition of 58. For instance, for a 158 rotation of patch 1, the pattern shift was 108 in the clock wise direction. Whereas, patch 2 rotation of 158 resulted pattern shift of 108 in anticlockwise direction and so on. Similarly, in the unbiased situation of the diodes between small strip and larger patch will result radiation pattern switching from 58 to 308 at 3.3 GHz by rotating the patch with an increment of 7.58.
4 | RESULTS AND DISCUSSION A prototype of the layout shown in Figure 1 was printed on a 1.524 mm thick, low loss Rogers TMM4 laminate (Er 5 4.5, tan d 5 0.002) for the proof of concept of radiation
Measured radiation patterns when patches are resonating at 3.3 GHz. (A) PIN diode 1 is biased, and (B) PIN diode 2 is biased
2184
|
pattern shifting for the proposed design. The photograph of the fabricated prototype is shown in Figure 5.
4.1 | Return loss The measurements were taken using a well calibrated Agilent N5242A PNA-X network analyzer. The measured return loss was better than 10 dB in the both bands. When PIN diode 1 and diodes between small strip and larger patch 1 were biased, the patch 1 resonated at 2.43 GHz, whereas patch 1 resonated at 3.3 GHz in the unbiased situation of diodes between small strip and larger patch 1. This frequency reconfiguration mechanism of patch 1 is depicted in Figure 6. In the similar fashion, patch 2 exhibited return loss characteristics for biasing, un-biasing of PIN diodes between smaller strip and larger patches, and biasing condition of diode 2. There was a slight variation observed in the measured result in comparison with simulated results. These dissimilarities are because of the fabrication imperfection and lossy connectors.
4.2 | Antenna far-field characteristics The radiation pattern of the fabricated antenna shown in Figure 5 was measured and is shown in Figures 7 and 8. The radiation patterns of the proposed antenna were measured at both switching frequencies as shown in Figures 7 and 8. In Figure 7A, when diode 1 is biased, the diodes on patch 1 were also biased to resonate the patch 1 at 2.43 GHz and radiation pattern towards 308 in the xz-plane. Similarly, when diode 2 was biased, only patch 2 was activated and PIN diodes on patch 2 were activated to switch the radiation pattern to 2308 in the xz-plane as shown in Figure 7B. In Figure 8, the radiation patterns at 3.3 GHz are plotted when diode 1, diode 2 were biased one by one, and other PIN diodes were unbiased. It can be observed from Figure 8 that the pattern shift was 308 and 2308 for patch 1 and patch 2, respectively. The measured gain in the ON mode of PIN diodes was 4.9 dBi, while gain of 5.5 dBi was observed in the OFF mode of PIN diodes. The lower gain value at 2.43 GHz is because of the losses of PIN diodes.
5 | CONCLUSION A complete demonstration of concept for achieving frequency and radiation pattern reconfigurability simultaneously of microstrip patch antennas is presented in this article. It is shown that frequency is reconfigured by changing the effective length of the patch antenna by the incorporation of diodes. Whereas, a single feed was used for the excitation of two microstrip patches. The operation of wave propagation and radiation mechanism for both the
KHAN
ET AL.
patches is achieved by in succession connection of feed line using PIN diodes 1 and 2. The pattern phase shift was achieved by the mechanical rotation of individual patches with respect to angle u. The proposed design was capable of switching frequencies between 2.43 and 3.3 GHz. It is also shown that rotation of patch 1 in the clockwise direction resulted maximum phase shift 308. While, phase shift of 2308 is achieved by rotating patch 2 in clock-wise direction. The wide range flexibility of the proposed design in terms of frequency and radiation pattern reconfigurability makes this design a promising candidate in modern wireless communication systems. R EFE RE NC ES [1] Trong NN, Hall L, Fumeaux C. A frequency and polarization reconfigurable stub-loaded microstrip patch antenna. IEEE Trans Antenn Propag. 2015;63:5235–5240. [2] Khan MS, Capobianco A-D, Iftikhar A, Asif S, Ijaz B, Braaten BD. A frequency reconfigurable series-fed microstrip patch array with interconnecting CRLH transmission lines. IEEE Antenn Wireless Propag Lett. 2015;15:242–245. [3] Khan MS, Capobianco A-D, Naqvi A, Shafique MF, Ijaz B, Braaten BD. Compact planar UWB MIMO antenna with ondemand WLAN rejection. Electron Lett. 2015;54:963–964. [4] Khan MS, Capobianco A-D, Iftikhar A, Asif S, Ijaz B, Braaten BD. An electrically small CPW fed frequency reconfigurable antenna. In: IEEE APS, Vancouver, BC, Canada; 2015: 2391– 2392. [5] Yang XS, Wang BZ, Wu W, Xiao S. Yagi patch antenna with dual-band and pattern reconfigurable characteristics. IEEE Antenn Wireless Propag Lett. 2007;6:168–171. [6] Chen SH, Row JS, Wong KL. Reconfigurable square-ring patch antenna with pattern diversity. IEEE Trans Antenn Propag. 2007;55:472–475. [7] Jusoh M, Aboufoul T, Sabapathy T, Kamarudin MR. Patternreconfigurable microstrip patch antenna with multidirectional beam for WiMAX application. IEEE Antenn Wireless Propag Lett. 2014;13:860–863. [8] Christodoulou CG, Tawk Y, Lane SA, Erwin SR. Reconfigurable antennas for wireless and space applications. Proc. IEEE. 2012;100:2250–2261. [9] Brown ER. RF-MEMS switches for reconfigurable integrated circuits. IEEE Trans Microwave Theory Tech. 1998;46:1868– 1880. [10] D, Piazza P, Mookiah M. D’amico, Dandekar Experimental analysis of pattern and polarization reconfigurable circular patch antennas for MIMO antennas. IEEE Trans Antenn Propag. 2010;59:2352–2362. [11] Bai Y, Xiao S, Liu C, Shuai X, Wang B. Design of pattern reconfigurable antennas based on a twoelement dipole array model. IEEE Trans. Antennas Propag. 2013;61:4867–4871. [12] Khan MS, Capobianco A-D, Asif S, Iftikhar A, Ijaz B, Braaten BD. Compact 4 3 4 UWBMIMO antenna with WLAN band rejected operation. Electron Lett. 2015;51:1048–1050.
MUNIZ
|
ET AL.
[13] ANSYS, Ansys HFSS-High frequency electromagnetic field simulation software, Available online: http://www.ansys.com/Products/Electronics/ANSYS-HFSS [last accessed date: December 5, 2016].
2185
signal-to-noise ratio, linearity, constellation, and error vector magnitude. KEYWORDS
5G networks, four-wave mixing, microwave photonics, mm-waves, radio-
How to cite this article: Khan MS, Iftikhar A, Capobianco A-D, Shubair RM, Ijaz B. Pattern and frequency reconfiguration of patch antenna using PIN diodes. Microw Opt Technol Lett. 2017;59:2180–2185. https:// doi.org/10.1002/mop.30709
Received: 10 February 2017 DOI: 10.1002/mop.30704
All-optical RF amplification toward Gpbs communications and millimeter-waves applications Andre L. M. Muniz1 | Dionisio F. Noque1 | Ramon M. Borges1 | Antonella Bogoni2 | Masaaki Hirano3 | Arismar Cerqueira Sodre Jr1 1
Laboratory WOCA, National Institute of Telecommunications (INATEL), Santa Rita do Sapucaí, Brazil 2
Scuola Superiore Sant’Anna, Pisa, Italy
3
Sumitomo Electric Industries, 1 Taya-cho, Sakae-ku, Yokohama 244-8588, Japan Correspondence Arismar Cerqueira Sodre Jr, Laboratory WOCA, National Institute of Telecommunications (INATEL), Santa Rita do Sapucaí, Brazil. Email:
[email protected] Funding information Finep/Funttel, Grant/Award Number: 01.14.0231.00; FINEP; CNPq; CAPES; MCTI; FAPEMIG
Abstract We propose and experimentally investigate the use of an ultra-wideband photonics-assisted RF amplifier for Gbps communications and mm-waves applications, including 5G cellular networks. A 2 Gsymb/s broadband signal with different modulation formats has been used for evaluating the all-optical RF amplifier, as a function of diverse electrical and optical figures of merit, including RF gain,
frequency amplifier
1 | INTRODUCTION New internet services have been emerging, such as high definition video stream, bitpipe communications at Gbps, tactile Internet, Internet of things (IoT), rural access networks, and autonomous car. In parallel, new challenges, including spectrum, propagation channel, reliability, cost and energy efficient aspects become extremely important for the successful of future wireless networks. More specifically, it is envisioned throughputs of 10 Gbps for enabling virtual reality and immersive experience, latency lower than 1ms for making self-driving cars and intelligent traffic management become a reality in future cities and billions of connections due to the exponential growth of IoT. Millimeter-waves (mm-waves) have been recognized as a potential frequency band for fulfilling the tough requirements of this new generation. However, the generation, detection, and amplification of mm-waves are very challenging due to limitations and complexity of the electronics components for this frequency range.1 Moreover, wireless transmission of mm-waves suffers from very high path-loss. In this context, radio over fiber (RoF) systems and photonics-based RF devices have been recognized as potential solutions for mm-waves applications, including 28 and 38 GHz that are potential bands for the fifth-generation (5G) cellular systems.2 The 5G networks are likely to operate in the centimeter-wave (3–30 GHz) and mm-wave (30–300 GHz) frequency bands, in which there is a lot of unexploited spectrum worldwide. Recent progress on microwave photonics3–6 and nonlinear optics have indicated a breakthrough in optical-wireless communications due to the possibility of enabling RF signal amplification in the optical domain.5 The proposed device is recognized as photonics-based RF amplifier (PBRA) and takes advantage of the nonlinear effect four-wave mixing for providing RF gain, as a consequence of parametric amplification. Furthermore, we have recently demonstrated a photonics-based RF front-end for 5G networks.6 It uses the single-MZM upconversion technique and the nonlinear effect multiple four wave mixing (FWM) to simultaneously perform ultra-broadband RF upconversion and photonicsassisted microwave amplification, respectively. Its main functionalities are frequency tunability, broadband operation, and distortion absence.
