LTCC Transmit/Receive X-Band Module with a Phased Array Antenna
7 www.cadence.com/go/awr
Step 5: Designing and Simulating the Signal Path
Next, the Analyst software was used to design and simulate the signal path, with transitions from the MMIC PDK to the LTCC
PDK using dual bondwires. Because it is a 3D EM simulator, the Analyst software can work with multiple technologies, which,
in this example, includes a gallium arsenide (GaAs) MMIC pad, an LTCC pad, and a bondwire model. The distance between the
bondwires and their length was optimized and the transitions were optimized up to 50GHz.
Using External Library Parts
Instead of designing a MMIC from scratch, external library parts were imported into the model, including a PA driver, a phase
shifter, and an attenuator. The cell was generated, named, and then imported. This was easily done in a schematic that is
synchronized with the layout (Figure 12).
Figure 12: External library parts were imported into the model; the schematic was synchronized with the layout
Designing the Filter
The Cadence AWR iFilter™ synthesis wizard was used to design a stripline bandpass filter (BPF) using the iFilter interdigital option
(Figure 13). The filter was imported into the model, optimized in the AWR Microwave Office software, and directly EM simulated
and optimized using the AWR AXIEM EM simulator (Figure 14). Once optimized, it was then re-embedded in the model.
Figure 13: The iFilter interdigital option was used to design a stripline BPF
Figure 14: The filter was simulated and optimized directly in the AWR AXIEM simulator
