S INGLE -B ALANCED M IXER P ROJECT D ESIGN R EVIEW RIT Senior Project Jared Burdick Held May 3, 2012 Updated May 5, 2012 with Action Items

A GENDA Schedule Specifications Block diagram Components used Design decisions / trade-offs AWR model Simulation results Circuit layout Fabrication / assembly Testing Action Items & Notes from Review

S CHEDULE Key Milestones Concept Design selections Model build / simulation Design review Fabricate circuit & mixer assembly Test assembly Evaluate results Write report Demonstration at RIT Completion Date March 23 April 13 April 26 May 3 May 11 May14 May 16 May 21 TBD

S PECIFICATIONS

B LOCK D IAGRAM

C OMPONENT L IST RF splitting (1) Anaren SMD Hybrid Coupler Diodes (2) Avago RF Schottky-barrier series pair (1) LPF (1) Lumped element maximally flat – 5 th order RF connectors (3) SMA female jack end-launch printed circuit board mount Printed circuit functions (on RO4003, 32-mil thick, 1oz. copper) RF chokes – shorted λ/4 stub (2) Impedance transformer - λ/4 (1) 50 Ω lines (5)

S UBSTRATE M ATERIAL

H YBRID C OUPLER

S CHOTTKY D IODES

L OW -P ASS F ILTER

SMA C ONNECTORS

P RINTED L INE C ONSIDERATIONS RF chokes Maximized line width vs. performance to gain production margin (narrow line-widths more difficult to produce). Need to stub is well grounded – brought it close to the edge where a strap can be installed. Quarter-wave impedance transformer Meandered to minimize the size of the circuit substrate. Tapered the line where it met component pads. Mitered corners. 50 Ω interconnects Mitered corners. Grounding Added ground to the top of the circuit board wherever possible to reduce impedance. Will connect top & and bottom planes with wires and straps. This would normally be accomplished with plated via’s. Component pads Used manufacturers’ recommendations.

D ESIGN D ECISIONS M ADE / T RADE -O FFS RF Splitting Looked at 90, 180 degree couplers. 90-degree easier to implement. Surface mount standard product readily available from Anaren (distribution) & inexpensive. Greatly simplifies the circuit board. Filtering Removed BPF’s in the RF and LO paths Not readily available or too expensive. Not enough time to design lumped-element realizations. Not critical to performance or meeting specification. LPF (IF path) Maximally flat – desire good pass-band flatness and suppress the 1.0 GHz LO leakage. Lumped-element – distributed too large, components are inexpensive. 5 th order (see design and simulation later). Purchase coils, use DLI capacitors.

D ECISIONS / T RADE -O FFS RF Chokes Started with radial transformers (λ/2 open stubs). Did not simulate very well – higher conversion loss & poor flatness. Moved to λ/4 shorted stubs (high impedance). Diodes Avago Schottky series pair diodes selected. Using a pair improve diode match (to each other). Also purchased Infineon pair as a risk reduction (same package so they can be installed on existing circuit). Substrate Material Rogers RO4003 selected. Low-cost microwave material. FR-4 could potentially be utilized – risk item (higher loss, more ε r variation) 32-mil thickness selected to provide some rigidity for the soldered components and the connectors. 1-oz copper used due to soldering, particularly the connectors – fear that 0.5 oz would tear or lift during hand-solder operations.

AWR M ODEL

S IMULATION R ESULTS

RF = 1.0 GHzRF = 0.8 GHz RF = 0.9 GHzRF = 1.15 GHz

S IMULATION R ESULTS

C IRCUIT L AYOUT Circuit is 2.0” x 2.5” x 0.032” RO4003 – 1oz. Copper both sides Orange areas are circuit traces Green areas are ground Backside is all ground Will incorporate drilled holes and ground interconnect wires from top- bottom surfaces. Will install edge-wrapped straps from top-bottom surfaces. SMA Conn Launch (RF In) SMA Conn Launch (LO In) SMA Conn Launch (IF Out) LPF λ/4 transformer Diode Pair Coupler λ/4 shorted stub

F ABRICATION & A SSEMBLY Circuit to be fabricated at Anaren using LPKF prototype circuit router. Approximately 4 circuits will be produced initially – more if needed. Will require some hand de-burring of copper. Inside corners will not be 90-degrees, there will be a small radius base on the diameter of the end-mill used. The small gap for the LPF shunt capacitors may have to be hand cut with a scalpel. Circuit assembly will be performed by Anaren Assembly Technician Basic soldering of components using manufacturer’s recommendations where possible (recommended footprints were incorporated in the design/layout). Manual soldering of ground connections from top to bottom copper layers using: Edge-wraps Wires through drilled holes.

T ESTING Testing to be performed at Anaren Conversion Loss Isolations (RF-IF, LO-IF) VSWR’s (RF, LO, IF ports) 1-dB Compression Spurious Response Test Equipment Required Spectrum Analyzer RF Signal Generators (2) Power Meter SMA Male 50 Ω Terminations (2) Test Cables (3) Adapters (as required) Sample Size One piece initially Additional (1-3) after

A CTION I TEMS & N OTES F ROM R EVIEW