RF Attenuators

Purchased Attenuators

Programmable Attenuator

• PE4302 RF Attenuator board in my enclosure design

Triple Attenuator

• 0/10/20/30 dB Attenuator

Homebrew RF Attenuators

Homebrew RF Attenuators

Attenuator Design - Rev 2

• 6 dB resistor values in above
• OshPark clear soldermask "After Dark"
  • $4.40 for 6 cards
• Small/light enough to hang directly off fragile devices
• SMA connectors
  • Male/female are good choices for direct connect to devices
• Resistors
  • 1206
    • 1/4W
    • 1% values get good accuracy (approx. 2%) even though not exact to calculated values
• Good bandwidth up well past RF

Parts

Mfr. #	Manufacturer	Customer #	Qty	R1/R2	Description
RK73H2BTTE17R8F	KOA Speer	ATTEN_03DB	1	R1	Resistors - SMD 1/4W 17.8 ohms 1%
RC1206FR-07294RL	YAGEO	ATTEN_03DB	2	R2	Resistors - SMD 294 ohms 1/4W 1206 1%
RK73H2BTTD37R4F	KOA Speer	ATTEN_06DB	1	R1	Resistors - SMD 1/4W 37.4 ohms 1%
CRCW1206150RFKEAC	Vishay	ATTEN_06DB	2	R2	Resistors - SMD 1/4Watt 150 ohms 1%
RC1206FR-0771R5L	YAGEO	ATTEN_10DB	1	R1	Resistors - SMD 71.5 ohms 1/4W 1206 1%
RC1206FR-0797R6L	YAGEO	ATTEN_10DB	2	R2	Resistors - SMD 97.6 ohms 1/4W 1206 1%
RK73H2BTTD1070F	KOA Speer	ATTEN_13DB	1	R1	Resistors - SMD 1/4W 107 ohms 1%
RC1206FR-0778R7L	YAGEO	ATTEN_13DB	2	R2	Resistors - SMD 78.7 ohms 1/4W 1206 1%
AC1206FR-07249RL	YAGEO	ATTEN_20DB	1	R1	Resistors - SMD 249 ohms 1/4W 1206 1%
RK73H2BTTDD61R9F	KOA Speer	ATTEN_20DB	2	R2	Resistors - SMD 61.9 ohms 1%
RK73H2BTTD7870F	KOA Speer	ATTEN_30DB	1	R1	Resistors - SMD 1/4W 787 ohms 1%
AC1206FR-0753R6L	YAGEO	ATTEN_30DB	2	R2	Resistors - SMD 53.6 ohms 1/4W 1206 1%
RC1206FR-072K49L	YAGEO	ATTEN_40DB	1	R1	Resistors - SMD 2.49k ohms 1/4W 1206 1%
RK73H2BTTD51R0F	KOA Speer	ATTEN_40DB	2	R2	Resistors - SMD 1/4W 51 ohms 1%
RK73H2BTTDD49R9F	KOA Speer	ATTEN_50_60DB	2	R2	Resistors - SMD 49.9 ohms 1%
RC1206FR-077K87L	YAGEO	ATTEN_50DB	1	R1	Resistors - SMD 7.87k ohms 1/4W 1206 1%
RC1206FR-0726K1L	YAGEO	ATTEN_60DB	2	R2	Resistors - SMD 26.1k ohms 1/4W 1206 1%

Measurements

• NanoVNA
• S21 gain
• 1-900 MHz scan
• Calibrated with cable on thru

6 dB Attenuator

• Flat from 1-600 MHz
• Higher attenuation past 600 MHz
• S21

• S11 from 1-900 MHz

40 dB Attenuator

• Flat from 1-600 MHz
• Higher attenuation past 600 MHz
• -39.9 dB at 14 MHz
• S21

• Flat from 1-30 MHz
• S21

• s11
• 1-900 MHz

• VSWR
• 1-900 MHz

DC Block

• Use same PCB
  • Install 0.1uF cap between the two SMAs
  • Leave off resistors to ground
• Sweep 50 KHz to 900 MHz
• S21 of -0.8 dB at 50 KHz
• S21 of 0.44 dB at 900 MHz

• Sweep 50 KHz to 900 MHz
• S11

Attenuator Charts

References

• Attenuator Calculator - Le Leivre.com
• Attenuator Calculator - Pasternak

• Heavily inspired by Alan (W2AEW) video