IoT & Wireless Hardware Design
JUZHITECH designs wireless hardware for BLE, Wi-Fi, LoRa, and NB-IoT devices, covering RF PCB layout, antenna integration, and low-power architecture. We conduct design-stage EMC reviews and coordinate RF measurements and pre-compliance testing with specialist partner labs.
The Gap
Three situations where the RF details make or break your product.
"Our dev kit gets 100 meters. The custom PCB gets 10 meters."
This happens when an RF layout treats a 2.4 GHz trace like a standard digital signal. Without a continuous reference plane, precise via stitching, and a coplanar waveguide (CPWG) geometry, your RF energy radiates into the board instead of the antenna.
"Our spreadsheet predicted 2 years. The prototype dies in 3 months."
You cannot fix a leaky hardware design in firmware. If your PCBA lacks physical load switches to kill power to quiescent sensors, or uses an LDO with high quiescent current (Iq), your battery will drain regardless of your RTOS sleep state.
"The board failed FCC radiated emissions at the test lab."
A noisy DC-DC switching regulator placed too close to the RF front-end, or an improperly grounded shield can, will generate spurious emissions. Failing FCC/CE certification at the end of the project causes catastrophic schedule delays.
Protocol Selection
Choosing the right physical layer for your IoT product.
The RF protocol dictates your BOM cost, battery size, and antenna geometry. We evaluate these trade‑offs during Phase 1 Architecture.
| Technology | Band | Range | Data Rate | Power | Chip Platforms | BOM Cost & Complexity |
|---|---|---|---|---|---|---|
| BLE 5.x | 2.4 GHz ISM | 10–100 m | 125 Kbps – 2 Mbps | Ultra-low | Nordic nRF52/53, TI CC26xx, ESP32-C/S | $ Low · Fast entry — mature SDKs, pre-certified modules available |
| Zigbee / Thread | 2.4 GHz ISM | 30–100 m (mesh) | 250 Kbps | Low | Silicon Labs EFR32, TI CC26xx, Nordic nRF53 | $$ Medium · Protocol complexity adds firmware effort, mesh certification required |
| LoRa / LoRaWAN | Sub-GHz (868/915 MHz) | 2–15 km | 0.3–50 Kbps | Ultra-low | Semtech SX126x/127x, ASR6601, STM32WL | $$$ Higher · Sub-GHz antenna tuning is unforgiving, gateway infrastructure needed |
| NB-IoT / LTE-M | Licensed cellular | 1–10 km (cellular) | 20–250 Kbps | Low | Quectel BG95/BC95, SIMCom SIM70xx, u-blox SARA | $$ Medium · Carrier certification + SIM provisioning, but no gateway needed |
| Wi-Fi 6 (802.11ax) | 2.4 / 5 GHz | 30–100 m | Up to 9.6 Gbps | Medium–High | Espressif ESP32-C5/C6, NXP RW61x, Infineon AIROC | $ Low · Extremely mature ecosystem, lowest barrier to entry |
Technology selection is a hardware decision with firmware and certification consequences. A LoRa module on a 4-layer FR-4 board needs a different antenna topology than a Wi-Fi 6 module on a 6-layer controlled-impedance stackup. The chip platform column reflects the IC families our RF team has delivered production firmware on — not a generic compatibility list. We make the technology and platform recommendation during Phase 1 architecture, based on your deployment environment, volume, and certification path.
RF & Power Architecture
Physics, not software. How we engineer reliable wireless PCBA.
RF PCB Layout — isolating the analog domain.
Routing a 50Ω trace is only the baseline. We enforce strict RF layout disciplines: continuous, unbroken ground planes beneath the entire RF path. Precise via stitching along the edges of the coplanar waveguide (CPWG) to suppress substrate resonance. We physically isolate noisy digital buses and switching regulators from the sensitive analog front-end (AFE) using guard traces and physical distance.
Antenna Tuning — the Pi-network and the VNA.
An antenna's resonant frequency shifts dramatically when the PCBA is placed inside a plastic enclosure or near a human body. We never assume the datasheet impedance is final. We design a Pi-matching network footprint at every antenna feed. Once the physical prototype is inside its final housing, we coordinate S11 return-loss measurement with our RF partner lab and populate the exact inductor/capacitor values required to hit a perfect 50Ω match.
Ultra-Low Power Architecture — hardware-level gating.
True low-power IoT devices rely on hardware architecture, not just firmware sleep modes. We design power trees using nano-power buck/boost regulators with Iq in the nanoamp range. We deploy physical load switches (MOSFETs) to completely sever power to high-drain sensors and SD cards when not in use, eliminating leakage current. The RTC (Real-Time Clock) and wake-up domains are strictly isolated from the main MCU power rail.
In Practice
Three wireless designs where the RF details made the difference.
Smart Lock (BLE)
By re-architecting the power tree with dedicated MOSFET load switches, we eliminated peripheral leakage current during the MCU's deep sleep cycle, extending the 4xAA battery life from 8 months to 2.5 years.
Industrial Gateway (LoRa)
The original layout suffered from severe antenna detuning due to a nearby metal chassis. We re-calculated the CPWG trace width and tuned the Pi-network — with return loss measured by our RF partner lab — increasing effective range by 40%.
Medical Wearable (Wi-Fi/BLE)
We deployed a customized shielding can over the RF front-end and optimized the decoupling capacitor placement on the MCU power rail, design changes that carried the board through radiated emissions at the accredited lab on the first submission.
Common Questions
IoT & wireless hardware design FAQ.
Do you design custom PCB antennas or use off-the-shelf components ?
We do both, depending on your space and BOM cost constraints. We frequently design PCB trace antennas (like the Inverted-F Antenna, MIFA) because they reduce BOM cost to zero. For space-constrained wearables, we integrate ceramic chip antennas. For metal enclosures, we route to a U.FL connector for external antennas. Regardless of the type, every antenna requires physical tuning on the final board.
Why does antenna matching need to be done on the actual board ?
Because your enclosure, battery, display, and component placement all detune the antenna. The antenna reference design from the manufacturer was measured on their evaluation board — a bare PCB with no enclosure, no battery, and a ground plane sized for optimal performance. Your product has a plastic housing 3 mm from the antenna, a Li-Po battery 12 mm beneath the ground plane, and a metal mounting bracket. Each of these shifts the antenna’s resonant frequency.We measure S11 on the actual board in the actual enclosure — via our RF partner lab — then adjust the matching network until the antenna is tuned for your environment — not the manufacturer’s evaluation board.
What's the difference between pre-compliance scanning and full certification?
Pre-compliance scanning is a diagnostic step run by an accredited partner lab — it identifies emissions likely to exceed regulatory limits, so layout fixes happen before the formal test. Our role is the design-stage EMC review that prevents most failures: shielding, decoupling, return paths, and switching-node layout, verified before the board ever reaches the lab. Full certification is the formal test by an accredited lab (TÜV, SGS, Eurofins) that produces the report required for FCC/CE marking. Most designs that skip pre-compliance fail their first certification attempt — which costs $8,000–20,000 and weeks of schedule.
Pre-certified module vs. discrete RF transceiver — how do we choose ?
A pre-certified module (e.g., u-blox, Quectel) costs more per unit but saves $10k+ in FCC/CE certification fees and reduces RF layout risk. It is almost always the right choice for volumes under 50,000 units. A discrete RF design (chip-on-board) requires rigorous layout and expensive certification, but reduces BOM cost at high volumes. We present this ROI calculation during the architecture phase.
How We Deliver
RF engineering available through three engagement models — as a specialized function within your project.
Joint Design (JDM)
You write the IoT cloud application and device logic. We design the RF PCB, match the antenna, and write the low-level wireless drivers.
Explore JDM →Full Turnkey ProductTurnkey ODM
You define requirements — we own the full firmware development, hardware integration, production test, and lifecycle under one roof.
Explore ODM →