LTE Cat 1bis or 5G RedCap? RF design decisions behind an IoT modem refresh

What happened

This is a technical analysis article discussing how choosing among LTE Cat 1bis, LTE-M, NB-IoT, and 5G RedCap when refreshing an IoT cellular modem affects RF design. It states that RedCap has moved beyond specifications and demonstrations: a growing range of Release 17 chipsets, modules, and industrial devices is commercially available, operators are enabling it on 5G standalone networks, and GCF introduced RedCap certification in 2023 and certified the first RedCap module in 2024. Cat 1bis uses ordinary LTE infrastructure, retains Cat 1's nominal 10-Mbps downlink and 5-Mbps uplink, and reduces the receiver to one antenna path, with comparisons putting the resulting sensitivity or coupling-loss penalty at roughly 3 to 4 dB relative to Cat 1. RedCap, introduced in 3GPP Release 17, has a maximum 20 MHz bandwidth in FR1 without carrier aggregation, and in FR1 allows either one or two receive branches, requiring dual-antenna mechanical provisions when two branches are used. The article also covers low-band coverage around 600 to 960 MHz, coexistence and interference with GNSS/Wi-Fi/Bluetooth antennas, PCB ground-plane effects and over-the-air testing via TRP and TIS, PTCRB/GCF certification and operator acceptance, and cites the Taoglas and Telit Cinterion Cat 1bis reference design pairing an ELS62-W module with a PCS.50.A tunable antenna. Release 18 eRedCap aims to further reduce 5G device complexity, with commercial chipsets and devices expected in early 2027, remaining a roadmap consideration. The article contains no price movement, capacity, inventory, or trade policy information.

Impact and signal

Affected components and suppliers

Source and time

Source: EDN · 11/10/2026 · View original source