System Level Design Review

System Level Design Review PO94 Microwave Data II Joel Barry Amanda Kristoff Mia Mujezinovic Michael Pecoraro

P094 Microwave Data II Technical Review Agenda Meeting Purpose: This meeting is to review the system and components to confirm it meets the Functionality, ngineering Specifications and Customer Needs of the P094 Microwave Data II KGOC MSD team. Materials to be Reviewed: Project Overview (Rev. A) Customer Needs Chart (Rev. B) Customer Specifications Chart (Rev. B) Customer Needs to Specifications Chart (Rev. B) Concept Generation/System Level Design (Rev. A) Risk Assessment (Rev. A) ngineering Design Process (Rev. A) Component and System Progress Report (Rev. A) Two Quarter Schedule/Milestones (Rev. B) Meeting Date: January 16, 2009 Meeting Location: 78-2150 Meeting time: 12:0 2 PM Timeline: Start Time Topic of Review 12:0 Team Introductions 12:5 Project Overview 12:40 Concept Generation/System Level Design 12:50 Risk Assessment 12:55 ngineering Design Process 1:05 Component Progress: Branchline Hybrid 1:10 Component Progress: Knochel Hybrid 1:15 Component Progress: Schiffman Phase Shifter 1:20 System Progress: System A 1:25 System Progress: System B 1:0 Two Quarter Schedule 1:40 Question

Introduction Mia Members: Mia Mujezinovic (Team Lead) Michael Pecoraro Amanda Kristoff Joel Barry Breakdown of Roles/Tasks: 90 Degree Hybrid: Michael Pecoraro 180 Degree Hybrid: Joel Barry Schiffman Phase Shifter: Mia Mujezinovic System A: Mia Mujezinovic System B: Amanda Kristoff Vertical Launch: Anaren, Joel Barry, Michael Pecoraro DG Updates: Amanda Kristoff Ansoft Designer Ansoft HFSS I Xplorer Database Michael nders (Anaren, customer) Resources Utilized:

Project Overview Michael Customer Michael nders RF ngineer Anaren Microwave Incorporated Space and Defense Group Menders@anaren.com 15-62-027 Project To design, build and verify the operation of two 4x4 Butler Matrices for use in antenna beamforming Figure 1: Block Diagram of System A Figure 2: Block Diagram of System B Purpose Butler Matrices are networks that allow antenna beams to be electrically (as opposed to physically) steered. The necessary condition for electrically steering an antenna beam is that the antenna elements must be given different phase progressions. This is what a Butler Matrix does depending on which input is used, a different phase progression is realized at the output. This project is more of a research type project for Anaren. They have two main goals that they would like us to attain: o Both Butler Matrices should be wideband covering a bandwidth of 10-12GHz o Anaren has never used a Knöchel hybrid - they would like to see how it performs individually as well as in a system

Concept Generation / System Level Design Joel Layout Stackup Chosen Stackup Copper Ground Plane Alternative Stackup 1.5 mil 60 mil 60 mil Rogers 00 Arlon 6700 Copper Traces Rogers 00 Copper Ground Plane 0 mil 0 mil Figure : Anaren specified stackup designs for implementation into both Butler Matrices. The only difference between the two stackups is the thickness of the Rogers 00 dielectric. The 120 mil stackup will be implemented in the Butler Matrix Designs for some key advantages: o Thicker dielectric yields thicker traces for equal impedance lines ensures traces will be greater than the minimum manufacturing tolerance of 10 mil o Thicker traces are less susceptible to variation with the width tolerance of 0.5 mil 1.5 mil Topology Selection By unfolding the crossovers of the Butler Matrix A design, a single copper trace layer that mirrors the symmetry of the 90 coupler. Butler Matrix B is similarly unfolded to a single copper trace Vertical Mounting SMA connectors allow for access to all ports without implementation of crossover networks. Figure 4: Selected topologies for the Butler Matrix A Design (Top) and the Butler Matrix B Design (Bottom).

Risk Assessment Amanda Risks that have been addressed: Understanding the theory behind the components Understanding customer expectations/needs Learning HFSS Understanding ideal simulation tool in Ansoft Designer Risks that still need to be addressed or considered: o Finalize and reevaluate specifications from Anaren o Vertical mount (receiving documentation from Anaren, designing and effects at system level needs to be considered) o Lead time on board manufacturing is 6 weeks

Process Michael An extremely simplified process (or flow) by which we have been working to complete this project is seen below: Theory Ideal Simulations Designer Simulations HFSS Simulations Figure 5: Project Flow Chart This process applies to each component and system that we will design. To explain the above process a bit further, read below: Theory - verything begins with theory there are textbook entries and papers written on each of the components that we are building (not necessarily the systems, but definitely on Butler Matrices in general). We read them, check them and fully understand them before getting started with any type of simulations. When we feel we are ready to start simulating, we go to the next level: Ideal Simulations - This type of simulation is done in Ansoft Designer using the special ideal components. These components do not take into account any losses and show the absolute best case performance of your component or system. Impedance values, electrical lengths and frequencies are determined by the papers that were read (formulas would be given) and depending on the specific specifications for the project. Designer Simulations - Once the ideal simulations are completed, one can now include the substrate effects, discontinuities and other losses into the system using Ansoft Designer. These simulations will be, clearly, worse than the ideal simulations. The ideal simulation is, however, your goal; you always check back to see how well you can match it. Designer allows for many variables to be tuned in real time. Intelligent tuning, however, takes into account your ideal values and theoretical dependencies. HFSS Simulations - Once the designer simulation has been finished, the final step is tuning in HFSS. Using the theoretical dependencies and the ability of designer to see, magnitude-wise, how much these changes affect the output variables, the final tweaking is done. Again, this process applies to both the component level and system level designs. This is the most efficient way of simulating otherwise, you would have no real basis for what you are doing you would be blindly tuning variables and hoping for the best.

Port4 =90deg Z=a =90deg =90deg Z=a Port1 Port2 Port Component Progress - Branchline Hybrid Michael Ideal =90deg =90deg =90deg =90deg =90deg =90deg =90deg =90deg Figure 6: Schematic View of Ideal Branchline Hybrid Figure 7: S-Parameters of Ideal Branchline Hybrid Figure 8: Output Phase Difference for Ideal Branchline Hybrid Ideal values were obtained from the paper: A Multisection Broadband Impedance Transforming Branch-Line Hybrid; I Transaction on Microwave Theory and Techniques. Formulas were given for theoretical values of impedances these were solved for a line impedance of 50 ohms. Results are as expected: over the entire bandwidth of 10-12GHz, there is equal power division between ports two and three and a 90 degree phase difference between ports two and three.

Component Progress - Branchline Hybrid Michael Designer (Initial 120mil) Figure 9: Schematic View of Designer Hybrid Figure 10: Layout View of Designer Hybrid Figure 11: S-Parameters of Designer Hybrid Figure 12: Output Phase Difference for Designer Hybrid Variable Value [mm] Value [mil] fifty 1.9762 77.80407 down.77688 148.69606 mid 4.48688 176.648819 a 0.684897 26.9644488 b 2.95945 116.5178 c b d a The tune feature was used to tune the lengths and widths of the transmission lines the values seen in the table to the left were found to give the best performance Although not as perfect as the ideal results, the simulated results are quite good we have approximately equal power division between ports 2 and and there is approximately a 90 degree phase difference between ports 2 and.

Component Progress - Branchline Hybrid Michael Designer (Second Cut 120mil) Figure 1: Schematic View of Second Cut Hybrid Figure 14: Layout View of Second Cut Hybrid Figure 15: S-Parameters of Second Cut Hybrid Figure 16: Output Phase Difference for Second Cut Hybrid Variable Value [mm] Value [mil] fifty 1.9762 77.80407 down.78 148.818898 mid 4.49 176.771654 a 0.70 27.5590551 b.00 118.11026 c b d a qwt 2.2 87.7952756 Quarter Wave Transformers (QWTs) were included at each of the four ports. These widths tuned, as well as the other lengths and widths to produce the table found to the left. Transmission did not change much, neither did the phase. However, the return loss and isolations improved to approximately 22dB down.

Component Progress - Branchline Hybrid Michael HFSS (Initial) Figure 17: D View of HFSS Branchline Hybrid Figure 18: Power fficiency of HFSS Branchline Hybrid Figure 19: S-Parameters of HFSS Branchline Hybrid Figure 20: Output Phase Difference for HFSS Branchline Hybrid The xport to HFSS option in Ansoft Designer was used to create the HFSS model seen in Figure 12. This model, when simulated, has major problems. Figure 1 shows the power efficiency of this model as can be seen, over half of power over the entire 10-12GHz bandwidth is being lost somewhere. From the simulated S-Parameters we see that the transmission is no longer 50:50 and that the reflections and isolations have risen. The phase difference plot shows that the phase difference is approximately correct, but has worsened from the Designer simulation.

Port Port2 F =11GH z =45deg Z =86.0 Z =91.96 =180deg F =11GH z =60deg F =11GH z Z =50 =60deg F =11GH z Z =50 =90deg F =11GH z Z =69.64 =180deg F =11GH z Z =41.7 =180deg F =11GH z Z =69.97 =90deg F =11GH z Z =69.64 Component Progress - Knöchel Hybrid Joel Ideal =90deg Z=55.78 =90deg Z=77.81 Port1 =60deg =90deg Z=49.95 =15deg Z=86.0 Port4 =90deg Z=55.78 =90deg Z=77.81 =60deg Figure 21: Schematic View of Ideal 180 Hybrid Coupler Figure 22: S-Parameters of Ideal 180 Hybrid Coupler Figure 2: Output Phase Difference for Ideal 180 Hybrid Coupler Ideal values were obtained from the paper: Broadband Printed Circuit 0 /180 Couplers and High Power Inphase Power Dividers; I Transaction on Microwave Theory and Techniques. Designer simulations were presented for a 50 ohm line impedance. The results are as expected. Over the entire desired bandwidth of 10-12GHz, there is equal power division between ports two and three and a 180 phase difference between ports two and three when power is applied to port four.

Port W=0.54949mm P=7.86751mm W=1.05529mm ANG=5deg R=1e-020mm W=1.05529mm ANG=55deg R=1e-020mm W=0.54949mm W=0.65787mm P=.976mm W=0.65787mm P=1.96688mm W=2.68mm P=7.86751mm W=1.054mm P=7.86751mm W=1.9762mm Component Progress - Knöchel Hybrid Joel Designer (Initial 120 mil) Port2 Port2 W=1.05529mm P=.976mm 2 1 W=1.9762mm W2=1.05529mm W1=1.6679mm W=1.6679mm P=.976mm W1=1.6679mm W2=0.8586mm W=2.68mm 1 2 W=0.8586mm P=.976mm W1=0.8586mm W2=1.054mm Port1 2 1 W=1.9762mm W=0.54949mm P=.976mm W2=1.9762mm W1=1.9795mm 1 2 4 W=1.9795mm W1=1.9795mm W=0.65787mm P=.976mm W2=1.05529mm P=5.9006mm W=0.65787mm W4=1.05529mm W1=0.65787mm W2=0.65787mm Port1 R=1e-020mm ANG=5deg W=1.05529mm W=1.05529mm P=.976mm R=1e-020mm ANG=55deg W=1.05529mm W=1.9762mm P=.976mm W1=1.05529mm W2=1.6679mm W=1.9762mm 1 2 2 1 W=1.6679mm W=2.68mm P=.976mm W2=1.6679mm W1=0.8586mm W=0.8586mm P=.976mm 2 1 W=1.054mm W2=0.8586mm W1=1.9762mm Port4 W=1.9762mm P=.976mm Port4 Port Figure 24: Schematic View of Designer Hybrid Figure 25: Layout View of Designer Hybrid Figure 26: S-Parameters of 180 Hybrid Coupler Variable Value [mm] Value [mil] $wfifty 1.9762 77.80407 $wz1 1.06491 41.9255905 $wz2 1.6679 64.4405511 $wz 2.68 10.67678 $wz4 0.8586 2.818464 $wz5 1.054 41.5090551 $wz6 0.65787 25.796456 $wz7 1.9795 77.942519 $wz8 0.54949 21.614567 Figure 27: Output Phase Difference for 180 Hybrid Coupler The tune feature was used to tune the lengths and widths of the transmission lines the values seen in the table to represent the widths of the different transmission lines based on the ideal impedances that will be tuned. With the addition of non-ideal corners, junctions and bends, the parasitic impedances of the lines have been changed, resulting in a shifted band of operation and relatively poor performance when compared to the ideal model.

W =$w fifty P=619.489m il W 1=$w fifty W 2=$w Z 1 W =$w Z 2 1 2 R =12m il AN G=180deg W =$w Z 6 Port1 P=70m il W =$w Z 6 W =$w Z P=$LZ W =$w Z 5 P=$LZ W =$w Z 8 P=$LZ 8 W 1=$w Z 1 W 2=$w fifty W =$w Z 2 1 2 W =$w fifty P=619.489m il Port4 Component Progress - Knöchel Hybrid Joel Designer (Second Cut 120 mil) Port2 W1=$wZ2 W2=$wZ4 W=$wZ W1=$wZ4 W2=$wZ5 1 2 W=$wZ2 W=$wZ4 P=$LZ4 P=$LZ4 W=$wZ1 P=$LZ1 W=$wZ1 P=$wZ2/2 P=7mil W=$wZ6 W=$wZ6 ANG=45deg R=12mil W=$wZ6 ANG=90deg 2 1 W=$wf if ty W=$wZ8 P=619.489mil W2=$wf if ty W1=$wZ7 W=$wZ7 P=154.872mil 2 1 4 W1=$wZ7 W=$wZ6 W2=$wZ1 P=25mil W=$wZ6 W4=$wZ1 R=0.001mil P=25mil W=$wZ6 P=$wZ2/2 W=$wZ1 W=$wZ1 P=$LZ1 2 1 2 1 W=$wZ2 P=$LZ4 W=$wZ W2=$wZ2 W=$wZ4 P=$LZ4 W=$wZ5 W2=$wZ4 W=$wf if ty P=619.489mil W1=$wZ4 W1=$wf if ty Port Figure 28: Schematic View of Designer Hybrid Figure 29: Layout View of Designer Hybrid Figure 0: S-Parameters of 180 Hybrid Coupler Variable Value [mm] Value [mil] $wfifty 1.9762 77.80407 $wz1 0.882 $wz2 2.0828 82 $wz 2.1082 8 $wz4 0.508 20 $wz5 0.866 4 $wz6 0.9144 6 $wz7 2.0574 81 $wz8 0.5588 22 Figure 1: Output Phase Difference for 180 Hybrid Coupler The tune feature was used to tune the lengths and widths of the transmission lines the values seen in the table to the left were found to give the best performance Although not as perfect as the ideal results, the simulated results are quite good relative to the initial trial we have approximately equal power division between ports 2 and and there is a normalized phase difference error of approximately +/- 0.4 between ports 2 and.

Component Progress - Schiffman Phase Shifter Mia The original Schiffman phase shifter design performed in Week 2 was scrapped completely and had to be redesigned. There was a misunderstanding of the purpose of the phase shifter and how it functions within the entire circuit. After a meeting with Michael nders at Anaren on 1/9/2009, the Schiffman phase shifter was re-designed from scratch. Ideal =90deg ZO=42 Z=66 Port1 Port2 Port =(180+45) deg Port4 Figure 2: Schematic View of Ideal Schiffman Phase Shifter Figure : Ideal Phase Difference Figure 4: Ideal Reflection and Transmission Losses The ideal model was developed using Schiffman s original paper published in the I Microwave Techniques Journal. B.M. Schiffman, A New Class of Broadband Microwave 90-Degree Phase Shifters, IR Trans. Microwave Theory Tech., vol. MTT-6, no. 4, pp.22-27. The results are: Over 10 12GHz, the phase difference between the reference line and the Shiffman phase shifter is 45 flat, with a return loss of -4.88dB at best between Markers 1 and. From the ideal model, even and odd mode impedances are extracted to be used in the real model. Z oe =66Ω and Z oo =42Ω

Port Port1 Port2 Port4 Component Progress - Schiffman Phase Shifter Mia Designer Because of the nature of the Shiffman phase shifter, the design cannot be modeled in Designer and then verified in HFSS. Attempts to model the phase shifter in Designer first have lead to failures. After speaking with Michael nders at Anaren, he suggested from his experience that the design be completed in HFSS, and Designer used to obtain starting values. As a sanity check, the ideal model was converted to a physical model with the chosen substrate of 121.5mil. P=L S=S W=W W=78.7771mil P=87.181mil Figure 5: Schematic view of semi-ideal phase shifter. Figure 6: Variable values for the phase shifter. Figure 7: Phase difference of semi-deal shifter. Figure 8: Reflection and transmission. From the figures above, it can be seen that the substrate does have some effect on the results. The phase difference is a bit flatter, and the return loss becomes a bit worse, with best case return loss of 1.07dB. The results above are the best possible results, and the model will be exported to HFSS and modified.

Component Progress - Schiffman Phase Shifter Mia HFSS The Schiffman phase shifter is designed primarily in HFSS. The ideal design does not take into account the thin strip of copper connecting the two coupled lines, and is nearly impossible to model in Designer. Also, port locations will become significant in the HFSS design. The design is still in progress, and results so far are unusable. Figure 9: D view of the Schiffman phase shifter, with chamfered edges.

Po r t1 Po r t2 =90deg =90deg = 9 0 d e g Z = a =90deg =90deg = 9 0 d e g Z = b =90deg =90deg = 9 0 d e g Z = a =90deg =90deg =(180+45) deg Port6 = 9 0 d e g Z = 5 0 = 9 0 d e g Z = b = 9 0 d e g Z = b = 9 0 d e g Z = 5 0 Port5 Z=66 ZO=42 = 9 0 d e g Z = 5 0 = 9 0 d e g Z = b = 9 0 d e g Z = b = 9 0 d e g Z = 5 0 =90deg Z=a =90deg =90deg Z=a =90deg Z=a =90deg =90deg Z=a =90deg Port8 = 9 0 d e g Z = 5 0 = 9 0 d e g Z = b = 9 0 d e g Z = b = 9 0 d e g Z = 5 0 Port7 = 9 0 d e g Z = 5 0 = 9 0 d e g Z = b = 9 0 d e g Z = b = 9 0 d e g Z = 5 0 Z=66 ZO=42 =90deg =(180+45) deg =90deg =90deg = 9 0 d e g Z = a =90deg =90deg = 9 0 d e g Z = b =90deg =90deg = 9 0 d e g Z = a =90deg =90deg Po r t Po r t4 System Progress - System A Mia Ideal Figure 40: Circuit layout of the ideal System A. Figure 41: Transmission from Port 1 to all outputs. Figure 42: Phase difference between output ports when Port 1 is input.

System Progress - System A Mia Figure 4: Reflection at all inputs. Figure 44: All S parameters. The above results are the best possible using all ideal components. The phase difference at the outputs when Port 1 is excited is 45 ±0.1. The best possible return loss is -2.18dB. All four outputs have about -6dB ±0.dB amplitude, meaning power is being split relatively equal between the four outputs, with each getting a quarter of the total input power

System Progress - System B Amanda Designer Port6 Port7 Port1 Port4 Port10 Port15 Port16 Port11 Figure 45: Schematic view of System B Figure 46: Layout view of System B Figure 47: Simulation results for input port 1 Figure 48: Simulation results for input port 2 Figure 49: Simulation results for input port Figure 50: Simulation results for input port 4 Simulation results show that there is a large amount of reflection at S55 and S66, these require the 180 degree Hybrid Coupler to be readjusted S78 also needs improved isolation, these will be re-evaluated after a new revision of the Hybrid Coupler is implemented