Printed circuit board (PCB) microstrip antennas belong to the family of Modern antennas; a category that undoubtedly remains very useful in multiple engineering areas such as aircraft, missiles, rockets, spacecraft -; not forgetting commercial areas like mobile satellite communications, global positioning system, Radio Frequency Identification (RFID), Worldwide Interoperability for Microwave Access (WIMAX), Radar Applications, Telemedicine Applications, military systems -, etc.
A transmitted signal is UWB if the RL absolute bandwidth exceeds 500 MHz  or the fractional bandwidth is more than 20% at −10 dB; noting that UWB utilization was authorized by the Federal Communications Commission (FCC) to (3.1 - 10.6) GHz in 2002 . According to  , printed monopole antennas have many possibilities for UWB performance; thus, the present research focus is put on UWB antennas in theory and practice.
2. UWB Antennas’ State of the Art
Some UWB signals were emitted by Hertz in 1887 , but the year 2002 awakened both academic and industrial research attention that is continually paid on UWB antennas -. Designers of monopole antennas look forward to reducing ground planes. According to the surveyed UWB antenna designs together with the history of UWB antennas, the reality is that UWB antennas existed for a couple of centuries ago  .
Learning from different authors, our aim now is to furthermore improve on bandwidth and radiation gain performance for PCB’s UWB antennas.
3. The Antenna Geometry, Design Methodology and Discussed Results
3.1. Design Structure and Methodology
A three dimensional solver high frequency simulator structure (HFSS) based on FEM  is the software tool selected for the present research. The 3D design model is presented in Figure 1(a). The main parts of the model: antenna as a top layer, ground as a bottom layer and the substrate as a keep-out layer were exported from Ansoft HFSS Modeler and manipulated with the conjunction of Auto CAD (Computer Aided Design) and Altium Designer’s Printed Circuit Board environment  to produce Figure 1(b), which is useful to manufacture the antenna.
For antenna synthesis, the RL is analyzed by time to time to decide on the necessary bandwidth performance. Analyzed over different substrates, the antenna RL results are two dimensionally exported to Microsoft Excel, as. csv format, later compiled together for comparison purpose. Origin Pro 8 for data analysis and graphing is the software tool utilized to prepare the data for Figure 2.
Figure 1. Design Model’s (a) three dimensional view; (b) top view.
Figure 2. RL with different substrates.
On RO3003C substrate material, the antenna does not only present optimal fractional bandwidth and radiation gain as detailed in Table 1, but also, the impedance matching with the input feed line is the most competitive for the pre-set frequency of 3.8 GHz. Therefore, all the results presented from Figures 3-8 relate to the antenna simulation on Rogers (ROO3C) substrate. Thus, for this specific research, the selection decision fell on Rogers RO3003C whose dielectric constant is 3.8.
3.2. The Simulation Results
3.2.1. The RL and Voltage Standing Wave Ratio
According to , the RL is the measure of how much of the available power is not delivered to the load. The
Table 1. Antenna bandwidths and gains with different substrates.
Figure 3. Optimal RL with rogers (RO3003C) substrate.
Figure 4. Impedance parameters.
Figure 5. Smith chart.
Figure 6. Radiation power pattern (a) in two dimensional view; (b) in three dimensional view.
reflection coefficient of a totally matched load is zero and its RL is infinity. The comparative RL when the unchanged antenna structure is analyzed over different substrate materials is shown in Figure 2. The optimal RL while the antenna printed over the selected substrate material is shown in Figure 3.
As for the antenna total efficiency (eT), according to , knowing the voltage reflection coefficient at input terminals, Γ, such that
, the input impedance;
(a) (b) (c)
Figure 7. Radiation fields’ overlay (a) 25%; (b) 50% overlay; (c) 100%.
, the transmission feed line’s characteristic impedance, equals to 50 Ω in normal conditions.
Mathematically, the antenna radiation efficiency is approximately unity since the antenna is simulated under perfect electric conduction (PEC) boundary. So, the computed total antenna efficiency is approximated to the mismatch efficiency; calculations were made possible by the measured impedance parameters in Figure 4. Both the total efficiency and VSWR are now calculated for a resonance frequency of 3.8 GHz.
3.2.2. Radiation Results
With the resonance frequency of either 3.8 GHz or 5.1 GHz, observable from the RL in Figure 3, carefully viewing UWB antenna standards -, the microstrip monopole antenna presented in this research paper is undoubtedly a high gain Antenna for UWB receivers and transceivers. It is expected to be an excellent candidate array element for base stations’ UWB array antenna; thus, highly boosting the obtained maximum radiation gain of 4.23 dB furthermore, in comparison with .
Application side, this UWB antenna is expected to find applications with Airport search radar, microwave relays, satellite down communications, Studio-To-Transmitter Link (STL) Microwave relays as well as satellite up communications, as illustrated in Figure 9, a summary made according to .
Excellent results were obtained by analyzing the antenna on Rogers 3003C, more competitive than on either Rogers 3003 or FR-4 (Epoxy); it has been made clear in Table 1. Optimally, the simulation reached to (3.3 - 5.8) GHz, absolute bandwidth, highly exceeding 500 MHz . The calculated fractional bandwidth is 67%, certainly greater than 20% . Radiation results indicate the omni-directional radiation; these are very appreciable parameters for UWB Antennas in general.
The pre-set goals to review and present the state of the art in UWB antenna has been successfully strengthened
Figure 8. Magnitude surface current density.
Figure 9. The antenna’s applications in the microwave spectrum.
by simulation results, presented here in this research article.
For the well conducted simulation, repeatedly yielding the same results, manufacturing results must certainly match with the simulation results.
We are in the process of manufacturing this antenna; it will then be tested and its measured results will be compared to simulation results. Our antenna prototype will undergo several modifications in order to finally hit the target furthermore.
A lot of gratitude is addressed to the Government of People’s Republic of China, to have supported and strengthened engineering research activities in the University of Science and Technology of China (USTC). Many thanks also go to the University of Rwanda, college of Science and Technology (UR, CST) for a couple of valuable supports.
 Lelaratne, R. and Langley, R.J. (2000) Dual-Band Patch Antenna for Mobile Satellite Systems. IEEE Proceedings on Microwaves, Antennas and Propagation, 147, 427-430. http://dx.doi.org/10.1049/ip-map:20000864
 Khondaker, R.M.H., Ahmed, S.S., Imran, K.M. and Nishat, S. (2014) Design of a Triple Band Microstrip Patch Antenna for Cellular and Wi-Fi Application. International Conference on Informatics, Electronics & Vision (ICIEV), Dhaka, 23-24 May 2014, 1-6. http://dx.doi.org/10.1109/ICIEV.2014.6850839
 Patel, S.K. and Kosta, Y.P. (2011) E-Shape Microstrip Patch Antenna Design for GPS Application. IEEE Nirma University International Conference on Engineering (NUiCONE), Ahmedabad, 8-10 December 2011, 1-4. http://dx.doi.org/10.1109/NUiConE.2011.6153261
 Ibrahim, R.A.R., Yagoub, M.C.E. and Habash, R.W.Y. (2009) Microstrip Patch Antenna for RFID Applications. IEEE Canadian Conference on Electrical and Computer Engineering, St. John’s, NL, 3-6 May 2009, 940-943. http://dx.doi.org/10.1109/CCECE.2009.5090266
 Mokhtar, M.H., Rahim, M.K.A., Murad, N.A. and Majid H.A. (2013) A Compact Slotted Microstrip Patch Antenna for RFID Applications. IEEE International Conference on RFID Technologies and Applications (RFID-TA), Johor Bahru, 4-5 September 2013, 1-4. http://dx.doi.org/10.1109/RFID-TA.2013.6694536
 Dwivedi, S., Rawat, A. and Yadav, R.N. (2013) Design of U-Shape Microstrip Patch Antenna for WiMAX Applications at 2.5 GHz. IEEE Tenth International Conference on Wireless and Optical Communications Networks (WOCN), Bhopal, 26-28 July 2013, 1-5. http://dx.doi.org/10.1109/WOCN.2013.6616214
 Amit, S.B. and Mithilesh, K. (2014) Microstrip Patch Antenna for Radiolocation using DGS with Improved Gain and Bandwidth. IEEE International Conference on Advances in En-gineering & Technology Research (ICAETR), Unnao, 1-2 Aug. 2014, 1-5. http://dx.doi.org/10.1109/ICAETR.2014.7012873
 Khaleel, H.R., Al-Rizzo, H.M., Rucker, D.G. and Elwi, T.A. (2010) Wearable Yagi Microstrip Antenna for Telemedicine Applications. IEEE Radio and Wireless Symposium, New Orleans, 10-14 January 2010, 280-283. http://dx.doi.org/10.1109/RWS.2010.5434177
 Ramasamyraja, R., Pandiguru, M., Arun, V. (2014) Design of Ultra Wide Band Antenna for Tactical Communication in Electronic Warfare. IEEE International Conference on Communication and Signal Processing (ICCSP), Melmaruvathur, 3-5 April 2014, 1256-1259. http://dx.doi.org/10.1109/ICCSP.2014.6950052
 Tatsis, G., Raptis, V. and Kostarakis, P. (2010) Design and Measurements of Ultra-Wideband Antenna. International Journal of Communications, Network and System Sciences, 3, 116-118. http://dx.doi.org/10.4236/ijcns.2010.32017
 Lak, H.J., Ghobadi, C. and Nourinia, J. (2011) A Novel Ultra-Wideband Monopole Antenna with Band-Stop Characteristic. Wireless Engineering and Technology, 2, 235-239. http://dx.doi.org/10.4236/wet.2011.24032
 Bakariya, P.S. and Dwari, S. (2012) A Compact Super Ul-tra-Wideband (UWB) Printed Monopole Antenna. Proceedings of IEEE 5th International Conference on Computer and Devices for Communication (CODEC), Kolkata, 17-19 December 2012, 1-3. http://dx.doi.org/10.1109/codec.2012.6509206
 Chang, F.-S., Lin, C.-Y., Chen, H.-T. and Chao, K.-C. (2005) A Novel Monopole Antenna Backed by a U-shaped Ground Plane for Multi-B and WLAN Application. IEEE International Workshop on Antenna Technology Small Antennas and Novel Metamaterials (IEEE iWAT2005), 7-9 March 2005, 517-520. http://dx.doi.org/10.1109/iwat.2005.1461130
 Wang, Z.D., Zhang, G.X., Yin, Y.Z. and Wu, J.J. (2014) Design of a Dual-Band High-Gain Antenna Array for WLAN and WiMAX Base Station. IEEE Antennas and Wireless Propagation Letters, 13, 1721-1724. http://dx.doi.org/10.1109/LAWP.2014.2352618
 Hans, G.S. (2004) A Brief History of UWB Antennas. IEEE Aerospace and Electronic Systems Magazine, 19, 22-26. http://dx.doi.org/10.1109/MAES.2004.1301770
 Mingyang, L. and Liu, M. (2014) Monopole Antenna and Dipole Antenna Design. In: Mingyang, L. and Liu, M., Eds., HFSS Antenna Design, 2nd Edition, Publishing House of Electronics Industry, Beijing, Chapter 3, 22-80.
 Xuefei, G., Yongli, A. and Jian, L. (2014) Principles of PCB Design. In: Xuefei, G., Yongli, A. and Jian, L., Eds., Altium Designer 10. Schematic Diagram and PCB Design Course, Beijing Hope Electronic Press, Beijing, Chapter 4, 69-95.
 Balanis, C.A. (2005) Fundamental Parameters of Antennas (Antenna Efficiency). In: Balanis, C.A., Ed., Antenna Theory Analysis and Design, 3rd Edition, A John Wiley & Sons, Inc., Publication, Chapter 2, pp. 64-66
 Min, J. and Shi-Lin, X. (2013) Design Principles and Applications of a Novel Electromagnetic Spectrum Table. IEEE Proceedings of the International Symposium on Antennas & Propagation (ISAP), Nanjing, 23-25 October 2013, 01, 184-187.