CRYSTALSIM

initializing lattice

Add Electromagnetic Coupling

Lesson 3 of 6·15 min read·+70 XP
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Wireless gating, in action

You have a crystal transistor with a piezo gate. The piezo gate already responds to mechanical stress — but how do we apply that stress at GHz frequencies? An EM antenna, tuned to the crystal's mechanical resonance. Time to wire it up.

Key Concept
Mechanical resonance
Every piezo crystal has a natural frequency at which it 'wants' to vibrate. Drive it at that frequency and the response amplifies by the quality factor Q (often 1000+). Drive it off-resonance and almost nothing happens.

Step 1 — Place the EM Antenna (Layer 6)

Open the Chip Builder. Drag an EM Antenna from the library onto Layer 6, directly above the piezo gate. The antenna is a λ/4 patch — its length determines the resonant frequency.

Step 2 — Wire antenna to piezo gate

Switch to the Wire tool. Connect Antenna → Piezo Gate. This routes the EM-induced potential into the gate input. (In a real device this 'wire' is the near-field coupling; in the simulator it's drawn as a connection.)

Step 3 — Power on and watch

Hit Power. You should see purple EM waves emanating from the antenna, the piezo gate visibly oscillating, and electron flow in the channel that turns on and off in sync. No physical wire to the gate terminal — the gate signal is arriving as RF.

Step 4 — Find resonance

Open the EM Coupling page. Sweep the drive frequency slider. You'll see the response curve peak sharply at one frequency — that's resonance. Off-resonance: tiny response. On-resonance: the gate swings hard with very little input power. This is the secret to ultra-low-power switching.

Checkpoint · +5 XP
Why does driving at resonance matter so much?

You just operated the full Crystal-EM Hybrid mechanism: ordered crystal channel, piezo gate, EM coupling. All three pillars in one device. Next lesson: prove it works by running every test the lab offers.

Lesson Summary
  • Add the EM Antenna Coupler to your crystal transistor.
  • Wire the antenna to the piezo gate.
  • Sweep frequency until the antenna hits resonance.
  • Watch EM waves drive the gate wirelessly.
Test Your Knowledge · +70 XP
1
Which layer does the EM Antenna sit on?
2
What does the antenna couple into?
3
What is mechanical resonance?
4
What's the quality factor Q?
5
Why is wireless gating useful?