================================================================================ SCHEMATIC: 4-WAY WILKINSON POWER DIVIDER TM-HYB-001 Rev A Two-stage binary tree, equal-split, in-phase, resistive isolation 50Ω system, covering 40M through 23cm ================================================================================ OVERVIEW -------- A 4-way equal-split divider constructed from three 2-way Wilkinson stages arranged in a binary tree. All outputs are in-phase (0° relative). Total insertion loss: 6.02 dB (3 dB × 2 stages). Topology: PORT 1 (input) ─── [Stage A: 2-way] ─┬─── [Stage B: 2-way] ─── PORT 2 │ └─── PORT 3 └─── [Stage C: 2-way] ─── PORT 4 └─── PORT 5 Stage A: Z0 = 50Ω input; two λ/4 arms of 70.7Ω; R_iso = 100Ω. Stages B, C: Z0 = 50Ω input (from Stage A output); same as Stage A. NOTE: Intermediate junction impedance = 50Ω throughout. The junction between Stage A output and Stage B/C input is 50Ω. No impedance transformation needed at junctions. COMPLETE SCHEMATIC (Lumped Element, HF) ----------------------------------------- PORT 2 │ [Stage B] [L_b2/2] [C_b2] [L_b2/2] │ │ R_iso_B (100Ω) │ │ │ PORT 1 ─┬─[L_a/2]─[C_a]─[L_a/2]─────────┬─────[Stage B] ─── PORT 3 │ │ [C_a] R_iso_A (100Ω) [R_iso_B = 100Ω shared] │ │ └─[L_a/2]─[C_a]─[L_a/2]─────────┴─────[Stage C] ─── PORT 4 │ R_iso_C (100Ω) │ [Stage C] ─────────────── PORT 5 TRANSMISSION LINE VERSION SCHEMATIC (VHF/UHF) ---------------------------------------------- PORT 1 (50Ω) │ │─── λ/4 @ 70.7Ω ────────────────── Node AB (50Ω) │ │ │ ├── λ/4 @ 70.7Ω ──[R_B=100Ω]── PORT 2 │ [R_A = 100Ω] (50Ω) │ │ │ └── λ/4 @ 70.7Ω ──┐── PORT 3 │ │ │─── λ/4 @ 70.7Ω ────────────────── Node CD (50Ω) (50Ω) │ ├── λ/4 @ 70.7Ω ──[R_C=100Ω]── PORT 4 [R_A = 100Ω] (50Ω) │ └── λ/4 @ 70.7Ω ──┐── PORT 5 │ (50Ω) R_A, R_B, R_C = 100Ω each (3 isolation resistors total) All λ/4 sections: 70.71Ω COMPONENT VALUES — LUMPED ELEMENT 4-WAY ----------------------------------------- (All three stages use identical L and C values at a given frequency.) Band f₀ (MHz) L_total/arm L/2 C_shunt R_iso (×3) ---- -------- ----------- ------- ------- ---------- 40M 7.15 1.574 µH 787 nH 315 pF 100Ω (×3) 30M 10.125 1.111 µH 556 nH 222 pF 100Ω (×3) 20M 14.175 793 nH 397 nH 159 pF 100Ω (×3) 17M 18.118 621 nH 311 nH 124 pF 100Ω (×3) 15M 21.225 530 nH 265 nH 106 pF 100Ω (×3) 12M 24.940 451 nH 226 nH 90 pF 100Ω (×3) 10M 28.850 390 nH 195 nH 78 pF 100Ω (×3) 6M 50.500 223 nH 111 nH 44.7 pF 100Ω (×3) Total components per unit: 6 inductors (L/2 each), 3 shunt caps (C), 3 × 100Ω NON-EQUAL SPLIT WILKINSON (Power Division Ratios) --------------------------------------------------- For unequal division (port 2: port 3 = k²:1): Z_arm_2 = Z0 × √(1+k²) / k (arm to high-power output) Z_arm_3 = Z0 × √(1+k²) × k (arm to low-power output) R_iso = Z0 × (k + 1/k) Common ratios: Split ratio k Z_arm_2 (Ω) Z_arm_3 (Ω) R_iso (Ω) ----------- --- ----------- ----------- --------- 50/50 1.0 70.7 70.7 100 75/25 1.73 58.1 100.0 144 90/10 3.0 52.7 158.1 317 These asymmetric dividers are useful for power monitoring (tap 10% for measurement, pass 90% to antenna). 8-WAY DIVIDER (3 STAGES) -------------------------- Add a third stage of 2-way Wilkinson after each of the 4 outputs. Total components: 7 isolation resistors, 7 × 2 inductor sets. Insertion loss: 9.03 dB. Maximum bandwidth: same as single stage (≈ 2:1). For wider bandwidth in multi-way dividers, use lossless reactive splitter (Gysel divider) or transmission-line tree with grounded resistors. PERFORMANCE SPECIFICATIONS — 4-WAY ------------------------------------- Parameter Specification --------- ------------- Insertion loss 6.02 dB nominal Port match (all) Return loss > 18 dB at design frequency Isolation (any 2 out) > 18 dB at design frequency Amplitude balance < 0.3 dB Phase balance < 2° Bandwidth (−1 dB) ≈ 1.5:1 frequency ratio Input/output Z 50 Ω PARTS LIST — 4-WAY WILKINSON (ONE UNIT) ----------------------------------------- Ref Qty Value Description --- --- ----- ----------- L1–L6 6 per table Series inductors (L/2 each arm) C1–C3 3 per table Shunt capacitors (C_shunt each arm) R1–R3 3 100 Ω Isolation resistors J1 1 SMA/BNC Input (port 1) J2–J5 4 SMA/BNC Outputs (ports 2–5) PCB 1 — See layout notes LAYOUT NOTES ------------- HF (through 30 MHz): Keep all component leads < 5 mm. Avoid ground loops between stages; use star ground at center. Shield stages B and C if inter-stage crosstalk is a problem. For outdoor use, pot finished board in urethane conformal coat. ================================================================================