Precision Conical Inductors Ultra Wideband Microwave Inductor Minimal Parasitic Capacitance

HALT20005 Conical Inductor Ultra-Wideband Performance Minimal Parasitic Capacitance Bias Tee Component

HALT20005 Conical Inductor — Ultra-Wideband Bias Tee Solution 200MHz–40GHz

The HALT20005 conical inductor is a precision-engineered broadband RF component utilizing a patented conical winding topology to deliver resonance-free inductive behavior across the full 200MHz to 40GHz spectrum. Unlike conventional planar spiral inductors that suffer from self-resonance within their operating band, the HALT20005 maintains pure inductive impedance with parasitic capacitance below 0.05pF, making it the definitive choice for bias tee circuits in next-generation RF and microwave systems.

Why Conical Geometry Matters

Traditional spiral inductors exhibit a fundamental trade-off: higher inductance requires more turns, which introduces inter-winding capacitance and creates a self-resonant frequency (SRF) within the operating band. The HALT20005 conical architecture solves this by progressively varying the turn diameter along the winding axis. The first turn (small diameter) handles the highest frequencies, while subsequent larger-diameter turns provide inductance at lower frequencies — all without creating a resonant peak. The result is a truly broadband device suitable for applications from HF through Ka-band.

Key Performance Characteristics

Bias Tee Application Optimization

The HALT20005 is specifically characterized for broadband bias tee applications where a DC bias must be injected onto an RF signal path without degrading signal integrity. Key advantages in bias tee circuits include:

• Ultra-low insertion loss: Less than 0.3dB across the RF path at 20GHz
• High RF-DC isolation: Greater than 30dB from 200MHz to 40GHz
• Minimal group delay variation: Less than 5ps across the operating bandwidth
• DC current handling: Up to 500mA continuous for active device biasing

Target Applications

• 5G NR Base Stations (FR1/FR2): Bias tee for LNA and PA biasing in n77/n78/n79 bands
• Satellite Communication: Wideband LNB and BUC bias injection circuits
• Electronic Warfare (EW): Instantaneous frequency measurement (IFM) receivers requiring octave-plus bandwidth
• Vector Network Analyzers: Bias tee integration in VNA test port extensions
• Phased Array Radar: T/R module bias networks for X-band through Ka-band systems
• Software-Defined Radio (SDR): Front-end bias networks covering 200MHz to 6GHz sub-6GHz bands

Technical Specifications

Frequently Asked Questions

Q: How does a conical inductor differ from a standard chip inductor?
A: A standard chip inductor uses uniform-diameter spiral windings, which create a self-resonant peak when inter-winding capacitance resonates with inductance. The HALT20005 conical inductor uses progressively increasing turn diameters, distributing the parasitic capacitance across a continuum of frequencies and eliminating any single resonant peak. This enables true broadband operation from 200MHz to 40GHz.

Q: What is the typical insertion loss in a bias tee using the HALT20005?
A: When properly impedance-matched, the HALT20005 contributes less than 0.3dB insertion loss at 20GHz. Total bias tee insertion loss depends on the companion capacitor and PCB layout; typical measured values for a complete bias tee design range from 0.5dB to 1.2dB across 200MHz–40GHz.

Q: Can the HALT20005 be used above 40GHz?
A: The HALT20005 is characterized and guaranteed from 200MHz to 40GHz. Above 40GHz, parasitic effects begin to introduce measurable deviation; however, many customers report acceptable performance to 50GHz in non-critical applications. For mmWave applications above 40GHz, contact our engineering team for application-specific recommendations.

Q: What PCB layout considerations apply?
A: For optimal performance, use a grounded coplanar waveguide (GCPW) or microstrip topology with 50-ohm impedance. Keep the RF trace from the inductor pad to the RF connector or device under 2mm to minimize parasitic inductance. Place the DC blocking capacitor within 1mm of the inductor pad for best bias tee performance. A continuous ground plane on layer 2 is essential.

Quality and Reliability

• 100% RF tested: Every unit undergoes S-parameter characterization from 10MHz to 43.5GHz before shipment
• MIL-STD-202 qualified: Passes thermal shock (Method 107), vibration (Method 204), and moisture resistance (Method 106)
• Gold metallization: 2.5-micron gold over nickel barrier ensures reliable wire bonding and solderability
• Traceability: Each reel includes a unique lot code with full manufacturing and test data available

Contact our applications engineering team today for detailed S-parameter data, evaluation board availability, and volume pricing on the HALT20005 conical inductor series.