V10.4 of the Ampsa Impedance-Matching Wizard has been released (Latest Build: 7250). The impedance-matching capabilities of the IMW were extended in this version. This includes a new error function for harmonic control and more options when fixed components are added to the terminations before a matching problem is solved.
The Windows interface and the program help were upgraded in V10.1 of the IMW. Several features were also implemented (V10.1) to simplify synthesis of matching networks based on load-pull data. In addition to point-matches, circular areas of allowable input or output reflection coefficients on the Smith Chart can now be defined and the circumferences of these circles, or the areas inside or outside the circles, can be set as targets for the input or output impedance of the matching networks to be synthesized. This is useful when the matching networks for high efficiency mode amplifiers are synthesized with Multimatch. This feature can also be used to map the constant gain circles (inherent stability required) and constant gain circles of linear amplifiers to equivalent IMW terminations.
Series lines could previously be added to the terminations of a matching problem to be solved. This capability has been extended to allow stubs and an additional series line to be added too before the matching problem is solved. The stubs can be used for biasing purposes or to force open or short terminations at the source or load termination for harmonic control.
Control over the 2nd and 3rd harmonic reactances are also provided when the bandwidth is less than an octave. A range of target reactance values can be set at each harmonic frequency. The resistance at the harmonic frequencies should ideally be zero, but this can only be realized at resonant frequencies. Instead, harmonic power is minimized by targeting high Q (X/R), or low or high input/output impedances for the matching network at the harmonic frequencies. More information is provided under Public Downloads (IMWV10_PowerMatchExample.pdf).
Many interface improvements were also made. This includes the option to copy the data in the IMW tables to the clipboard for pasting in programs such as Microsoft Excel (TM) and the option to hide some of the traces on a graph.The program and installer executables are now also digitally signed.
A list of recent changes is provided below:
- A correction was made to the constant mismatch circles displayed in the impedance-matching module. When no harmonic control is used and the results are displayed the reference planes are at input and output of the actual matching networks synthesized. When the harmonics are controlled, the reference planes are at the input and output of the complete network (matching network plus any connecting networks specified by using the File | Terminations | Add Lines command).
- Main-line lengths of 180 degree at any of the frequencies specified in the Impedance-Matching Module (harmonic frequencies included) should be avoided. The matching module uses lumped-element PI-sections or T-sections to model transmission lines during the synthesis process and the model is undefined at these lengths. This condition will be now be trapped and a warning will be issued.
- An issue with updating some of the tables in the Impedance-Matching Module was corrected.
- Only the line widths in the artwork were previously clipped to the artwork resolution. The line lengths are now also clipped to the resolution.
- The option to slope the gain (in dB) linearly or logarithmically with frequency was added.
- Negative lengths can now be assigned to the connecting lines specified for shunt capacitors or shunt inductors in the Impedance-Matching Module. This allows the lumped components to be moved closer to the main-line (less parasitic effects).
- Issues related to coarser settings of the artwork resolution (Artwork | Artwork Options and Parameters menu command) were resolved. The resolution should be higher than half of the smallest dimension used.
- Negative lengths can now be specified for the connecting lines added on the input or output side of the matching network to be synthesized (Specifications | Terminations | Add Lines command). This is useful for de-embedding lines added to measure the impedances of interest.
- The File | Import command can now be used to merge data from another IMW impedance-matching data file (.mmi) with the data associated with the active .mmi file. Different frequencies should be used in the two files (Use a slight offset in the actual frequencies if necessary). This feature is useful when matching networks for Doherty amplifiers are designed (the same matching network is then required to solve two different matching problems at the same time).
- The fixed elements allowed (source and load connecting networks cascaded with the matching network) were extended to allow a shunt capacitor and series inductor on the source side, and a series inductor and shunt capacitor on the load side. A shunt capacitor and/or shunt inductor is now also allowed in parallel with the stubs previously allowed. The fixed components allowed can be used to model the output circuit of a transistor in simple cases after which the intrinsic load line can be controlled.
- A correction associated with the new expanded fixed elements was made.
- The error function used when the harmonic terminations are controlled in the Impedance-Matching Module has been modified. Additional error factors (MRDf , MRD2ndH , MRD3rdH) are also now listed when a solution is displayed. These error factors provide numeric measures of how well the fundamental, second harmonic and third harmonic parts of the matching problem were solved (right-click the view for help). The option to revert to the previous error function is provided on the specifications dialog for the 2nd harmonic reactances (Specifications | Terminations | X2nd Harmonic command).
- When the option to slope the gain of an impedance-matching problem is used the option is now provided to scale the gain values in place with the values calculated. This provides an easy way of relaxing the gain-bandwidth constraints on a matching problem in a frequency-selective way.