RF PERFORMANCEENGINEERED FROMFIRST PRINCIPLES
Antenna design, link budgets, coexistence, and FCC compliance — from schematic to certified.
Ankh delivers RF and wireless engineering from link budget analysis and antenna selection through matching network design, multi-radio coexistence management, and FCC/ETSI certification support — working at the circuit level with S-parameters, Smith chart matching, and LNA/PA design, and at the system level with frequency planning and interference mitigation for products combining BLE, Wi-Fi, cellular, GNSS, and sub-GHz radios on a single PCB.
What We Engineer
Antenna Design & Matching Network
Chip antenna matching network optimization, PCB trace antenna design (meander line, inverted-F, PIFA), and patch antenna for fixed-mount applications — matching networks optimized on the Smith chart for minimum VSWR across the operating bandwidth.
Link Budget Analysis & System Planning
Per-link spreadsheets covering transmit power, antenna gain, path loss, Fresnel zone clearance, fade margin, and noise figure cascade — quantifying the relationship between antenna performance, radio selection, and achievable range.
Multi-Radio Coexistence Engineering
Full interference matrix analysis — isolation requirements, transmit spectral re-growth, and IMD products — driving PCB keep-out rules, RF switch architecture, firmware time-division schemes, and filtering to meet coexistence targets.
FCC & ETSI Regulatory Compliance
Pre-compliance RF testing covering FCC Part 15 Subpart B/C, Part 22, Part 90, ETSI EN 300 328, and EN 303 413 — with complete documentation for FCC TCB submission or CE technical file.
RF Shielding & Isolation Design
Shield can, tape, and gasket selection with aperture constraints, PCB footprint geometry, solder paste volume for reflow, and layer stackup adjustments for shielding effectiveness.
Custom Radio Frequency Circuit Design
Discrete front-end design for 900 MHz, 2.4 GHz, and 5 GHz — LNA bias optimization for minimum noise figure, PA matching for maximum PAE, T/R switch specification, and SAW/BAW filter selection — simulated in AWR Microwave Office or Keysight ADS.
Antenna Performance Measurement (TRP/TIS)
TRP/TIS coordination with accredited test facilities — device characterization, fixture design, and data analysis — plus assessment of whether module integration requires a permissive change filing or new equipment authorization.
GNSS Antenna Integration
Patch antenna LNA cascade design for GPS, GLONASS, Galileo, and BeiDou — PCB ground plane sizing, keep-out for adjacent metal, and LTE Band 13 desense analysis of GPS L1 (1575 MHz) via LNA compression.
How We Work
Wireless Requirements & System Architecture
A requirements session covers frequency bands, range targets, regulatory markets (FCC, CE, UKCA, ISED, MIC), antenna constraints, and coexistence requirements for all radios in the product. The output is a wireless architecture document specifying radio selections, antenna technology, coexistence strategy, and regulatory pathway.
Link Budget & Coverage Modeling
A quantitative link budget — transmit power, antenna gain, path loss, receiver sensitivity, and fade margin — models statistical coverage probability rather than free-space range figures that never match field experience. Budgets are updated after every prototype measurement cycle to close the model-to-measurement gap.
Antenna Design & PCB Layout Guidelines
Chip antenna matching networks are optimized on the Smith chart for minimum VSWR, accounting for form factor, metal proximity, and battery location. PCB trace antennas receive a keep-out zone and ground plane cutout; layout review confirms feed line impedance and RF test access.
Coexistence Analysis & Frequency Planning
The complete interference matrix — every radio's transmit spectrum mapped against every other radio's receive sensitivity — drives PCB isolation specifications: separation, ground stitching vias, band-reject filters, and RF switches. Firmware-level time-division coordination is captured in a coexistence interface document shared with the firmware team.
Pre-Compliance Testing & Iteration
Before a $15–25K test house submission, we conduct pre-compliance radiated and conducted emissions scans on first-article prototypes, resolving hardware failures (filter additions, shielding changes) before formal test. Our process typically catches 70–80% of test house findings, directly reducing first-pass failure rates and retest costs.
Regulatory Submission & Certification Support
The full technical documentation package for FCC TCB submission or CE technical file — test reports, block diagram, schematics, operational description, label drawings, confidentiality requests — is prepared and tracked through agency review, with all supplemental information requests answered through to FCC ID assignment.
The RF Engineering Details That Determine Field Performance
Antenna Matching: Smith Chart Optimization Beyond S11 Minimization
The correct target is minimum VSWR across the operating band, requiring the matching network to pre-rotate the antenna's impedance arc inside the VSWR = 2 circle — not just minimize S11 at center frequency. Ground plane size changes radiation resistance fundamentally; each solution is characterized empirically on the actual PCB.
Electronics DesignMulti-Radio Coexistence: The LTE/GPS Desensitization Problem
LTE Band 13 uplink at +23 dBm generates harmonics at 1554–1574 MHz adjacent to GPS L1 at 1575 MHz, producing −27 dBm at the GPS LNA input. Mitigation: GPS LNA with IIP3 > 0 dBm, SAW filter >50 dB rejection at the harmonic, and firmware pausing GPS acquisition during LTE uplink bursts.
Firmware DevelopmentFCC Part 15 Compliance Strategy: Passing the First Test
FCC Part 15 Subpart C testing costs $8–20K and takes 4–8 weeks — a first-pass failure is expensive. Pre-compliance explicitly targets the three most common failure modes: digital clock harmonics coupling onto antenna structures, PLL reference spurs, and PA power exceedance at band-edge channels across temperature.
Regulatory Certification
Antenna design, link budgets, coexistence, and FCC compliance — from schematic to certified.
RF & Wireless Engineering Across Ankh's Product Range
Every connected product has a wireless design challenge — our RF practice covers every frequency band and regulatory market relevant to the products we develop.
Wearable Electronics
On-body detuning characterization and matching compensation for BLE/NFC antennas adjacent to biological tissue
View ProductMedical Devices
FCC Part 15 and ETSI EN 300 328 certification coordinated with FDA 510(k) wireless coexistence testing
View ProductCold Chain Monitoring
LTE-M/NB-IoT antenna design for metallic shipping containers with link margin analysis for portal coverage
View ProductStructural Monitoring
900MHz LoRa link budget for NLOS propagation through concrete and rebar structural elements
View ProductIndustrial Equipment Monitoring
900MHz ISM antenna design and frequency planning for dense-metal industrial interference environments
View ProductAI Vision Systems
Wi-Fi 5GHz antenna placement for high-throughput video streaming with BLE and cellular coexistence isolation
View ProductPOS & Kiosk Hardware
FCC Part 15 and EMC compliance for kiosk enclosures with multiple intentional and unintentional radiators
View ProductWireless Communication
Frequency plan design for private LTE, CBRS, or licensed sub-GHz deployments with coordination documentation
View ProductData Loggers
BLE 5 long-range Coded PHY antenna optimization with passive NFC antenna for cost-optimized periodic config updates
View ProductRuggedized Devices
Aperture-loaded and ferrite-loaded helical antennas in metal enclosures, MIL-STD-810 vibration rated
View ProductSmart Home Automation
Matter/Thread 802.15.4 and Wi-Fi 2.4GHz coexistence analysis and FCC/CE certification for residential products
View ProductPower Monitoring
RF emissions compliance for SMPS harmonics and ZigBee/Z-Wave combinations in utility metering enclosures
View ProductFirst-Principles RF Analysis, Not Module Substitution
A smaller PCB, adjacent metal enclosure, or co-located radio can invalidate certified module conditions completely. Antenna impedance is measured on the actual PCB and matching networks are designed for the specific platform, not the reference design.
Pre-Compliance Testing That Prevents Test House Surprises
An FCC test house failure after 6 weeks and $15K in fees is almost always preventable with structured pre-compliance. LISN conducted emissions, radiated scans, and transmitter parameter measurement target the most common failure modes for each radio technology.
Coexistence Engineering Across the Firmware-Hardware Boundary
Hardware filters and PCB isolation are insufficient when firmware time-division arbitration isn't coordinated. The coexistence specification is owned end-to-end: firmware interface document written and the solution validated over the air, not just on a conducted bench.
Deliverables
Wireless System Architecture Document
Radio selections, frequency plan, regulatory pathway, coexistence strategy, and antenna technology direction with decision rationale.
Link Budget Analysis
Per-link spreadsheet: transmit power, antenna gain, path loss, noise figure, receiver sensitivity, fade margin, and coverage probability.
Antenna Design & Matching Network
Matching network schematic, Smith chart plots, VNA S11 data, and PCB layout guidelines with keep-out dimensions.
Coexistence Analysis Report
Full interference matrix, isolation calculations, and specified mitigation measures for each interferer-victim pair.
PCB Layout RF Review
Annotated layout review: antenna keep-out, transmission line impedance, shield can footprint, and RF test access points.
Pre-Compliance Test Report
Conducted and radiated emission data, comparison to regulatory limits, identified risk items, and recommended design changes.
FCC/ETSI Application Package
Complete FCC TCB or CE technical file: test reports, block diagram, schematic, operational description, label drawings, and confidentiality requests.
Coexistence Interface Specification
Firmware-facing document: radio arbitration rules, prohibited simultaneous operation combinations, and GPS acquisition scheduling requirements.
RF deliverable scope scales from a focused antenna matching engagement to a full multi-radio coexistence and certification program.
Often Paired With RF & Wireless Engineering
Electronics Design
RF front-end design and antenna matching are most effective when co-developed with the full schematic and layout.
ExploreFirmware Development
Multi-radio coexistence requires firmware-level arbitration implementing the radio scheduling policies defined in the coexistence interface document.
ExploreRegulatory Certification
RF pre-compliance feeds directly into the formal FCC, CE, and IC certification program, reducing test house cycle time and cost.
ExplorePCB Design
Antenna keep-out zones, impedance-controlled traces, and shield can footprints require close coordination between RF engineering and PCB layout.
ExploreWork That Demonstrates the Standard
Quad-Radio Coexistence Design for Industrial IoT Gateway
Ankh ran a full interference matrix for simultaneous BLE 5, Wi-Fi 802.11ac, LTE Cat-M1, and GPS on a 95×65 mm PCB — specifying a SAW filter (>45 dB at 1900 MHz), PTA arbitration, and LNA bias decoupling. GPS sensitivity measured −165 dBm with all radios active, 2.8 dB from GPS-only baseline against a −160 dBm spec, and the first FCC/IC submission passed.
Read the Case StudyCustom 915MHz Sub-GHz PCB Trace Antenna for Structural Sensor
Ankh designed a custom IFA with quarter-wave transformer sized for measured rebar detuning at 50 mm, fitting a 45×20 mm PCB inside concrete where rebar detuned standard chip antennas by 15–30 MHz. VNA on the concrete fixture confirmed 8 dB return loss across 902–928 MHz; TRP returned +2.1 dBi peak gain and 89% efficiency.
Read the Case StudyReady to Build RF That Performs in the Field and Passes Certification?Antenna design, coexistence analysis, and FCC/ETSI certification — from first schematic to grant.
Whether you need a matching network optimized for your specific PCB or a full multi-radio coexistence and certification program, Ankh engineers RF performance from first principles.