Welcome. Randy Rhea Founder of Eagleware & Elanix 2013 Agilent Technologies, Inc.

Transcription

1 Welcome Founder of Eagleware & Elanix 2013 Agilent Technologies, Inc.

2 Webcast: Designing Custom RF and Analog Filters through Direct Synthesis with examples from the new book Synthesis of Filters: S/Filter Techniques by (book available June 2014)

3 We'll Cover A two-slide review of the modern method The concept of transmission zeros (TZ s) in filter design Finding the optimum extraction sequence The application of canonic, noncanonic, exact, and inexact transforms Examples of filters with L-C components, TEM-mode coaxial resonators and quartz-crystals Slide 3

4 The Conventional Method Most filter programs today use the modern method developed in the 1950 s. Conventional designs of the modern method begin with a lowpass prototype and scale the impedance and frequency to desired values. For highpass, bandpass and bandstop, transformations are also applied. Slide 4

5 Genesys Programs That Use Conventional Methods The modern method is easy to apply. Genesys includes a variety of tools for this, that are integrated into an environment with schematic entry, layout, circuit-theory simulation and electromagnetic simulation. The Genesys modules used for conventional filter design are: PASSIVE FILTER: lumped-element lowpass, highpass, bandpass and bandstop filters in a variety of passband approximations and topologies. EQUALIZATION: designs all-pass group-delay equalizers for all filters designed in the Genesys suite or for S-parameter data. ACTIVE FILTER: designs filters that use operational amplifiers and R-C elements. MICROWAVE FILTER: a variety of distributed filters in a variety of realization processes such as microstrip, stripline, slabline and others. Genesys also includes tools for matching, signal control devices, mixers, oscillators, phase-locked loops, transmission lines, and system design. Slide 5

6 Direct Synthesis using Transmission Zeros This webcast covers a more powerful technique - direct synthesis. This technique uses the concept of transmission zeros (TZ s). L=73.89nH C=39.83pF L=126.11nH Infinity Slide 6

7 Transmission Zeros in a Bandpass How many TZ s at DC and infinity are in this bandpass filter? C=38.76pF C4 C=76.97pF C5 C=26.62pF L=196.24nH L=138.8nH C=67.05pF L=91.46nH C6 C=35.76pF L4 L=196.37nH C7 C=53.29pF C=202.78pF Slide 7

8 Multiple Extraction Sequences All of these filters have three TZ s at DC and three at infinity, and they have the same response as the conventional bandpass at the upper left. ZO=50O L=174.7nH C=15.5pF ZO=50O C=68.8pF L=39.3nH L=50.7nH C=53.3pF L=50.7nH C=53.3pF L=50.7nH L=11.4nH C=237pF C=53.3pF DC Inf Inf DC DC Inf DC DC DC Inf Inf Inf ZO=50O L=39.3nH C=305.8pF ZO=50O ZO=50O C=68.8pF L=8.8nH ZO=50O C=53.3pF L=11.4nH L=2.6nH C=1053.9pF L=50.7nH C=237pF L=2.6nH C=1053.9pF Inf Inf DC DC DC Inf T1 P=1 S=4.4 DC DC Inf Inf DC Inf T1 P=1 S=4.4 ZO=50O C=15.5pF L=776.7nH ZO=50O ZO=50O L=174.7nH C=3.5pF ZO=50O L=50.7nH C=53.3pF C=2.7pF L=225.4nH L=50.7nH C=12pF C=53.3pF L=1002nH DC Inf DC DC Inf Inf T1 P=1 S=0.2 DC Inf Inf Inf DC DC T1 P=1 S=0.2 Slide 8

9 Arbitrary Specification TZ s at DC and Infinity The quantity of TZ s at DC sets the low-side selectivity of a bandpass, while the TZ s at infinity sets the high-side. The conventional bandpass has an equal quantity of TZ s at DC and infinity. With synthesis, there is a choice. 3 TZ DC 3 TZ Infinity 1 TZ DC 5 TZ Infinity Slide 9

10 Finite Transmission Zeros (FTZ s) A Finite-Transmission Zero (FTZ) is a zero at a frequency between DC and infinity The Cauer-Chebyshev elliptic response places a specific quantity of FTZ s at specific frequencies to achieve equal minimum attenuation in the stopband. Direct synthesis supports placing FTZ s wherever they are required. Slide 10

11 The S/Filter Module in Agilent Genesys After you enter passband parameters and specify the placement of TZ s, the S/Filter program in Genesys finds the required synthesis polynomial, extracts element values for all unique sequences and displays the responses. You may interactively change entries as the response updates. You then select from a list of multiple solutions, each with a different schematic. Slide 11

12 Filter Degree Each TZ at DC adds one reactor and increases the degree of the filter by one. Each TZ at infinity adds one reactor and increases the degree by one. Each finite TZ (FTZ) adds three reactors and increases the degree by two. Slide 12

13 Example #1 - Arbitrary Placement of FTZ s ZO=50Ω C=2.08pF C=4.65pF C5 C=4.57pF C6 C=7.1pF ZO=50Ω L=180.82nH L=504.3nH L=290.67nH L4 L=180.82nH C=12.15pF C4 C=4.91pF C7 C=11.42pF Slide 13

14 Finding the Optimum Extraction Sequence Slide 14

15 Arithmetic Transmission Response Symmetry The conventional bandpass has an equal quantity of TZ s at DC and infinity. This naturally results in higher selectivity below the passband than above. This effect is more pronounced with increasing bandwidth. A ratio of 3 TZ s at infinity for each TZ at results in arithmetic response symmetry. L=36.14nH L=256.42nH C=73pF C=10.29pF L=21.23nH L4 L=150.61nH C=124.29pF C4 C=17.52pF L=36.6nH L=256.58nH C=9.34pF C=73.14pF C=1.25pF L= nH C4 C=0.58pF L4 L=182.88nH C5 C=12.81pF [1] R. Rhea, HF Filter Design and Computer Simulation, SciTech Publishing, Raleigh, NC, 1994 [2] R. Rhea, Exploiting Filter Symmetry, Microwave Journal, March 2001, pp Slide 15

16 Example #2 - A Generalized Symmetric Bandpass C4 C=14.14pF L=185.96nH C=49.86pF C=49.37pF C=36.19pF L=123.77nH L=89.56nH L4 L=185.99nH C6 C=78.25pF C7 C=32.95pF C5 C=376.71pF Slide 16

17 Integrated Network Transforms - Canonic S/Filter also integrates scores of network transforms for additional control of the final schematic. Canonic transforms modify the topology without adding additional components. L=36.6nH L=256.58nH C=73.14pF C=1.25pF C=9.34pF L= nH C4 C=0.58pF L4 L=182.88nH C5 C=12.81pF L=36.6nH L=256.58nH C=73.14pF C=30.76pF C=14.24pF C4 C=1.9pF L= nH C5 C=12.81pF L4 L=182.88nH Slide 17

18 Non-Canonic Transforms Other transforms increase the quantity of components but have other desirable attributes, such as eliminating a transformer, improving values, or creating all parallel or all series resonators. C=74.1pF L=4.05nH C=74.1pF L=32.47nH L=32.47nH C=463.11pF L=32.47nH C=26.16pF L=32.47nH C=47.94pF C4 C=26.16pF L=32.47nH C=23.88pF C5 C=47.94pF Slide 18

19 Norton Transforms A cornerstone, and the basis of some of the other transforms in S/Filter, are the Norton transforms. SHUNT SERIES Before Transform After Transform Before Transform After Transform Za Zc 1 : N 1 : N Z Zb Z Zb Za Zc 1 Z a 1 N Z 1 Z c 2 N N Z Z a 1 Z N Z c N Z N 1 Z b Z N Z b Z N Slide 19

20 Inexact Transforms The Norton, pi to tee, and other transforms are exact. S/Filter also includes inexact but useful transforms. One such transform is the Replace End Inverter with Capacitive L which is used to scale the internal impedance of a filter. Z in Z out Transform XC 1 Z in Z out Z in X Z 2 in X X 2 C 1 Slide 20

21 Coaxial Resonators Another inexact transform is the Parallel LC to Ground to Grounded Stub. This is used to design filters with ceramic-loaded TEM-mode resonators. For example, a Standard Profile Trans-Tech coaxial resonator with 8800 material has a Zo of 9.5 ohms. This equates to an effective L of 2.12 nh at 910 MHz. L C Zo L=90 Transform L 4Z 0 Slide 21

22 Filters with TEM-Mode Ceramic Resonators TEM-mode resonators are popular because of their high unloaded Q and good temperature stability. These filters are easily designed using many filter programs. C=1.78pF C=0.63pF C=0.48pF C4 C=0.63pF C5 C=1.78pF T Z=10.42Ω L=70.97mm K=1 T Z=10.04Ω L=73.7mm K=1 T Z=10.04Ω L=73.7mm K=1 TL4 Z=10.42Ω L=70.97mm K=1 Slide 22

23 Example #3 S/Filter adds the ability to specify FTZ s in filters using coaxial resonators. This example is a four-resonator filter with two FTZ s above the passband for exceptional high-side selectivity. C=2.23pF C=6.73pF C=0.7pF C4 C=6.73pF C5 C=2.23pF T Z=9.89Ω L=73.68mm K=1 L=3.45nH T Z=9.46Ω L=77.03mm K=1 T Z=9.46Ω L=77.03mm K=1 L=3.45nH TL4 Z=9.89Ω L=73.68mm K=1 Slide 23

24 Quartz-Crystal Resonators Very-narrow bandwidth filters are often constructed with quartz-crystal resonators which have exceptionally high unloaded-q and high effective inductance. Lm L=12.092mH Cm C= pF Rm R=11.6Ω Co C=5.45pF [1] R. Rhea, Discrete Oscillator Design: Linear, Nonlinear, Transient and Noise Domains, Artech House, Boston, 2010 Slide 24

25 Example #4 This example has four crystals and a bandwidth of 2 khz. Port_1 X1 R=11.6Ω L=12.092mH Cm= pF Co=5.45pF X2 R=11.6Ω L=12.092mH Cm= pF Co=5.45pF X3 R=11.6Ω L=12.092mH Cm= pF Co=5.45pF X4 R=11.6Ω L=12.092mH Cm= pF Co=5.45pF Port_2 C= pF C4 C= pF C6 C= pF Slide 25

26 Other Crystal Filter Examples in the Book The new book includes several example quartz-crystal and ceramic piezoelectric resonator filters design using synthesis Slide 26

27 Matching Genesys includes the Impedance Match which integrates numerous lumped and distributed routines into one environment. This is the best choice for difficult matching problems. When the need is for a filter with some matching, S/Filter is effective. ZO=50Ω C=59.02pF C= pF C4 C=87pF L= nH L= nH ZO=34Ω L= nH C= pF Slide 27

28 Distributed Filters S/Filter uses Richards transform for synthesis with arbitrary placement of TZ s and multiple extraction sequences, as was illustrated today for lumped filters. S/Filter also integrates a variety of network transforms used in distributed filters. Slide 28

29 Summary Most filter design software uses the modern method which became popular in the 1950 s The modern method has been applied to many filter types and is easy to use. Direct synthesis is a more powerful method of filter design S/Filter integrates synthesis and network transforms into the Genesys environment. The new book Synthesis of Filters: S/Filter Techniques was specifically written to guide and illustrate the synthesis design process. Slide 29

30 For More Info Questions about this presentation or the book: About Genesys: Genesys product page USA Genesys Specialist, Rick Carter richard_carter@agilent.com To obtain a free trial Genesys license with S/Filter: Go to Slide 30

31 You are invited to our next webcast Designing with 4G Modulated Signals for Optimized Multi-Standard Transceiver ICs October 3 7AM & 10AM PT Register for our live and recorded webcasts here: Andy Howard Senior Application Engineer Agilent EEsof EDA Juergen Hartung RFIC Product Marketing & Foundry Program Manager Agilent EEsof EDA Thank you Please complete the short survey following the end of this webcast.