Design of a Microstrip Patch Antenna
INTRODUCTION INTO RADIO FREQUENCY DESIGN AND THEORY MODULE NUMBER EP193 (THE PATCH ANTENNA DESIGN & SIMULATION ASSIGNMENT) By Yousif Sater MSc Optoelectronics and Communication with Management 03915418 Acknowledgment The author would like to take this opportunity to thank and acknowledge all that participated and helped this paper to go out as it is. ... THE MICROSTRIP ANTENNA 6 3. ... DESIGN PROCESS . ... THE TLIN LOSSLESS DESIGN 12 5. ... THE TUNING PROCESS OF THE DESIGN . ... REPLACING THE IDEAL TLIN WITH THE MICROSTRIP LINE . ... INVESTIGATION OF PRACTICAL ERRORS OF THE DESIGN . ... 27 1-ABSTRACT The aim of this report is to design a Square patch antenna. Some background introduction about the antennas in general followed by some more detailed theory about patch antennas finishing the background and theory with some introduction about Microwave Office simulation software. This antenna will use a Duroid substrate in its operation at 5GHz. The design calculations will be made, then using Microwave office the circuit will be simulated, first using ideal Lossless transmission lines with ideal junctions, where the length of the line was found to be 166. ... Then with a quarter transmission line transformer that was added to the design to tune its performance. The next simulation was then made using Microstrip transmission lines instead of the lossless lines used before, where the impact of such change was noted. Further more in this report an investigation was conducted regarding both substrate height errors and dielectric pemittivity errors, the changes to the design were calculated and then inputted into the design for it to be simulated to notice there effects on the general operation of the circuit. ... The radio antenna is an essential component in any radio system. ... One of the human beings and greatest natural resources is the electromagnetic spectrum and the antenna has been instrumental in harnessing this resource. ... 1-THE MICROSTRIP ANTENNA: For decades the microstrip antenna has been intensively used due to its significant merits of small size, light weight, low profile and its easy integration to circuits. An important application of microstrip antennas is the internal microstrip antenna that may be integrated into the PCB or plastic case of the telephone. ... Furthermore, a high level of shielding technology may be used to shield the internal antenna such that it has a negligible SAR value and is affected only by the human body. Probably the most promising technique to significantly reduce the interaction between the cellular telephone antenna and the human body is to use an internal integrated antenna such as a microstrip antenna. Microstrip antennas are considered one of the best candidates for such applications because they provide 50 Ohms input impedance and, thus, do not require a matching circuit. Microstrip antennas are relatively easy to manufacture accurately. Furthermore, microstrip antennas may be fed by coupling and, thus, eliminate physical contact between the antenna and the RF circuit. Moreover, it is relatively easy to separate the receiver and transmitter bands of microstrip antennas to eliminate the duplexer or at least make it easy to design. It is also relatively easy to design dual-band internal integrated microstrip antennas for PCS and cellular telephones. However, the microstrip antennas inherently have a narrow bandwidth. ... In general, the impedance bandwidth of a patch antenna is proportional to the antenna volume, measured in wavelengths. ... There has recently been considerable interest in the two layer probe fed patch antenna consisting of a driven patch in the bottom and a parasitic patch. Figure 1 below illustrates the design of a Microstrip antenna. Figure 1 the design of the Microstrip Antenna 3. ... As the whole process of the design was conducted using one of theses clever software packages. ... Microwave Office, is the design suite that completely revolutionized product development by shifting the balance of power back into the hands of high frequency design engineers. ... -schematic checks, statistical design capabilities, and parametric cell libraries with built-in design rule checking. This product is more capable and more powerful than any preceding generation or any other design tool on the market. ... The layout process for RF and microwave design is critical to overall circuit performance and must be closely connected to the simulation tools. ... The layout tool directly drives the simulation engine without any intervening netlist, and the layout-vs-schematic check is correct by virtue of a database structure that completely eliminates the need for back-annotation, forward-annotation, or any form of design synchronization. The result is a more integral solution than conventional microwave design tools that are built on a now antiquated software paradigm. 4-THE DESIGN PROCESS The assessment specification was to design a Square patch antenna with a frequency of 5GHz using a duroid substrate. The design Process started with the calculation of the Length and Width of the patch in order to determine the component values. ... Hence the width and length of the patch will be taken as 20. ... After calculating both dimensions of the patch the rest of the calculation can now be finished. ... The design of the square patch antenna is now completed as the theoretical component values were determined form the calculations and the process of designing the antenna and simulating the design using Microwave-Office which is the simulation package that is going to be used during this design deferent stages. ... 1-The TLIN lossless translation line design. As required by the assignment the first design was to be made using ideal lossless transmission lines and junctions. The diagram below illustrates the design with ideal components. (Figure 1) Figure 1 The Circuit as designed on Microwave Office After finishing the design (Appendix I), the circuit was simulated. ... This meant that the design must be tuned in a way to make it function correctly. ... 2 The Tuning process of the lossless transmission line design. ... However this method that was used ma not bee the proffered solution for such problem in real life situations as the transmutation line is narrow to be fabricated onto the patch and other solution maybe used, but as this assignment is only interested in simulation results and design no further solutions will be discussed. 6-REPLACING THE IDEAL TRANSMISSION LINE WITH MICROSTRIP LINE. For this part of the assignment the effects copper and dielectric losses where taken into account as the ideal lumped elements and transmission lines where replaced with microstrip transmission lines. The substrate that will be used fir this design was given as: The new MLIN transmission line replaced the TLIN line, (Appendix 9). However in the patch design it is not sensible to include T-junctions discontinuity between the input track and the patch because of the fact that the discontinuity was already taken into account in the equivalent network in the patch. In the other hand the circuit had to be refined in order to get it back to resonance, the dimensions of the patch had to be adjusted in order to do this. The new patch had a width and length of 18. ... Also a microstrip quarter line transformer was added to the circuit with a width of 0. ... Figure 2 The Microstrip patch antenna design The dimensions of the quarter length transformer are good for both of simulation and real life solutions as they have acceptable values. ... 7-THE INVESTIGATION OF PRACTICAL ERRORS OF THE DESIGN The aim of this part of the assignment is to calculate some of real time tolerance and manufacturers errors, as it is not possible under current technology to guarantee one hundred percent that the design specifications that were given by the customer and have been calculated are to be the once to be manufactured. ... Please not that the later is not applicable for this design as the simulation software wont be able to simulate such error. ... 240 The new values where feed into the design (Appendix 13) and the results of such changes where observed. ... The changes of the design components are summarized in the table below. ... 262 The new values where applied to the design (Appendix 17). ... S11 design detuned as the return loss changed to -35. ... 217 After the changes to the calculations have been made, they were applied to the design. ... 214 As always the new calculated values once again where input into the circuit design in Microwave Office. ... The design of the circuit with the given specifications where simulated first using the ideal lossless transmission line that was tuned to make it operate at the right frequency before replacing the ideal lines with a microstrip transmission line, before finishing with the investigation of fabrication and manufacturing errors. ... As the design had to be tuned in order to make it operational as required. This further press on the point that simulation packages even powerful and advanced once like the one that was here do not represent real life operation, keeping in mind that the author do agree that it dose give a near-realistic response and behavior of the design. Further more the investigation of the effects of errors that could occur in real life practical realization gave the author a glimpse at what effects errors in height and dielectric pemittivity could do to any given design that can happen during the operation of manufacturing and fabricating the circuit. ... This error may not have substantial effect on the operation of some products, but has a devastating effect on some other applications, therefore calculation of such error are essential to any given design of any circuit. 9-REFERENCES Text References: [1] Ramesh Garg, Prakash Bhatia, Inder Bahl and Apisak Ittipiboon, Microstrip Antenna Design Handbook, Artech House, Inc. ... Balanies, Antenna Theory Antenna Analysis & Design, 2nd Edition, John Willey & Sons, Inc. ... Raderick, Microstrip Antennas: Theory and Design, 2nd edition, Prentice Hall, 1981, International. [3] Kin-Lu Wong, Compact and Broadband Microstrip Antennas, John Wiley & Sons, 2002, International. [4] J Carr, Practical Antenna handbook, 4th edition, McGraw Hill, 2001, USA. ... Lee, Advances in patch & patch antenna, 1st edition, John Wiley & Sons, USA, 1997. ... THE TLIN DESIGN SCHEMATIC . ... THE SMITH CHART RESPONSE FOR THE TLIN DESIGN . ... THE SMITH CHAT FOR THE TLIN WITH TRANSFORMER DESIGN . ... S11 PARAMETERS CHART FOR TLIN WITH TRANSFORMER DESIGN . ... THE MLIN DESIGN SCHEMATIC . ... THE MLIN DESIGN IMPEDANCE RESPONSE . ... THE SMITH CHART RESPONSE CHART FOR THE MLIN DESIGN . ... THE S11 PARAMETERS RESPONSE CHART FOR THE MLIN DESIGN . ... 076MM DESIGN SCHEMATIC 40 14. ... 076 HEIGHT ERROR DESIGN . ... 076 HEIGHT ERROR DESIGN. ... 076 HEIGHT ERROR DESIGN. ... 076MM DESIGN SCHEMATIC 44 18. ... 076 HEIGHT ERROR DESIGN . ... 076 HEIGHT ERROR DESIGN. ... 076 HEIGHT ERROR DESIGN . ... 05 DESIGN SCHEMATIC . ... 005 PEMITTIVITY ERROR DESIGN . ... 005 PEMITTIVITY ERROR DESIGN . ... 005 PEMITTIVITY ERROR DESIGN 51 25. ... 05 DESIGN SCHEMATIC . ... 005 PEMITTIVITY ERROR DESIGN . ... 005 PEMITTIVITY ERROR DESIGN. ... 005 PEMITTIVITY ERROR DESIGN .55 INTRODUCTION INTO RADIO FREQUENCY DESIGN AND THEORY MODULE NUMBER EP193 (THE PATCH ANTENNA DESIGN & SIMULATION ASSIGNMENT) By Yousif Sater MSc Optoelectronics and Communication with Management 03915418 Acknowledgment The author would like to take this opportunity to thank and acknowledge all that participated and helped this paper to go out as it is. ... THE MICROSTRIP ANTENNA 6 3. ... DESIGN PROCESS . ... THE TLIN LOSSLESS DESIGN 12 5. ... THE TUNING PROCESS OF THE DESIGN . ... REPLACING THE IDEAL TLIN WITH THE MICROSTRIP LINE . ... INVESTIGATION OF PRACTICAL ERRORS OF THE DESIGN . ... 27 1-ABSTRACT The aim of this report is to design a Square patch antenna. Some background introduction about the antennas in general followed by some more detailed theory about patch antennas finishing the background and theory with some introduction about Microwave Office simulation software. This antenna will use a Duroid substrate in its operation at 5GHz. The design calculations will be made, then using Microwave office the circuit will be simulated, first using ideal Lossless transmission lines with ideal junctions, where the length of the line was found to be 166. ... Then with a quarter transmission line transformer that was added to the design to tune its performance. The next simulation was then made using Microstrip transmission lines instead of the lossless lines used before, where the impact of such change was noted. Further more in this report an investigation was conducted regarding both substrate height errors and dielectric pemittivity errors, the changes to the design were calculated and then inputted into the design for it to be simulated to notice there effects on the general operation of the circuit. ... The radio antenna is an essential component in any radio system. ... One of the human beings and greatest natural resources is the electromagnetic spectrum and the antenna has been instrumental in harnessing this resource. ... 1-THE MICROSTRIP ANTENNA: For decades the microstrip antenna has been intensively used due to its significant merits of small size, light weight, low profile and its easy integration to circuits. An important application of microstrip antennas is the internal microstrip antenna that may be integrated into the PCB or plastic case of the telephone. ... Furthermore, a high level of shielding technology may be used to shield the internal antenna such that it has a negligible SAR value and is affected only by the human body. Probably the most promising technique to significantly reduce the interaction between the cellular telephone antenna and the human body is to use an internal integrated antenna such as a microstrip antenna. Microstrip antennas are considered one of the best candidates for such applications because they provide 50 Ohms input impedance and, thus, do not require a matching circuit. Microstrip antennas are relatively easy to manufacture accurately. Furthermore, microstrip antennas may be fed by coupling and, thus, eliminate physical contact between the antenna and the RF circuit. Moreover, it is relatively easy to separate the receiver and transmitter bands of microstrip antennas to eliminate the duplexer or at least make it easy to design. It is also relatively easy to design dual-band internal integrated microstrip antennas for PCS and cellular telephones. However, the microstrip antennas inherently have a narrow bandwidth. ... In general, the impedance bandwidth of a patch antenna is proportional to the antenna volume, measured in wavelengths. ... There has recently been considerable interest in the two layer probe fed patch antenna consisting of a driven patch in the bottom and a parasitic patch. Figure 1 below illustrates the design of a Microstrip antenna. Figure 1 the design of the Microstrip Antenna 3. ... As the whole process of the design was conducted using one of theses clever software packages. ... Microwave Office, is the design suite that completely revolutionized product development by shifting the balance of power back into the hands of high frequency design engineers. ... -schematic checks, statistical design capabilities, and parametric cell libraries with built-in design rule checking. This product is more capable and more powerful than any preceding generation or any other design tool on the market. ... The layout process for RF and microwave design is critical to overall circuit performance and must be closely connected to the simulation tools.