Forefront RF Unveils Industry's First Commercial Low-Band Tunable Duplexer

Foretune technology replaces fixed SAW/BAW filters with a dynamically configurable architecture spanning 612–960 MHz

Forefront RF, a Cambridge-based fabless semiconductor scale-up, has unveiled what it believes to be the industry’s first commercially available low-band tunable duplexer module, the FFM51010. Enabled by its proprietary Foretune adaptive passive cancellation technology, the device eliminates the need for traditional SAW or BAW acoustic filtering, marking a significant shift in RF front-end design for cellular-enabled smartwatches, smartphones and other connected devices.

Today’s mobile devices rely on banks of duplexers, filters and switches, each restricted to a specific frequency band. As operators make additional spectrum available to meet growing data usage, manufacturers must support an increasingly fragmented global RF landscape. The result has been rising RF front-end complexity, larger component counts, regional differences in RF frequency bands, and increasing pressure in compact, space-constrained devices.

The FFM51010 addresses this challenge using Adaptive Passive Cancellation. Similar in principle to noise-cancelling headphones, which eliminate unwanted background sound by generating an opposing signal, the system creates an inverted replica of transmitter leakage and cancels it at the receiver input in real time. By actively suppressing this self-interference at radio frequency, the module replaces multiple fixed, band-specific filters with a single configurable solution while maintaining the linearity and stability required for increasingly complex multi-band devices.

“Despite longstanding research into reconfigurable RF systems, delivering a practical, high-linearity tunable duplexer suitable for high-volume cellular deployment has remained a significant technical challenge,” said Ronald Wilting, CEO of Forefront RF. “With Foretune, we are introducing configurability into one of the last rigid hardware blocks of the mobile radio.”

Key technical characteristics include:

• Receive frequency range: 612–960 MHz
• Transmit frequency range: 663–915 MHz
• Supported channel bandwidth: 1.4–20 MHz (higher bandwidth under development)
• Tunable duplex spacing: –46 MHz to +55 MHz
• Supported bands: 5, 8, 12, 13, 14, 17, 18, 19, 20, 26, 28, 71, 85, 105
• Integrated multi-mode power amplifier
• Integrated low-noise amplifier
• Integrated antenna-port bi-directional RF coupler
• No external duplexers required
• Single MIPI RFFE v3.0 interface
• LGA package: 6.0 × 4.5 × 0.75 mm

The device supports both Average Power Tracking (APT) and Envelope Tracking (ET) architectures and is targeted at 4G LTE, 5G NR and 5G RedCap user equipment, particularly single-antenna systems.

This first product release focuses on low-band spectrum. Future product generations are planned to extend the Foretune architecture into mid-band and high-band frequencies.

About Forefront RF
Founded in 2020, Forefront RF is a fabless semiconductor company poised to transform the way multi-band smartphones, wearables and other connected devices are designed. Based on award winning academic research, the company is developing a ground-breaking technology that reduces PCB space through fewer components and increases the number of supported frequency bands. With the mobile phone and adjacent markets embracing miniaturization, Forefront RFs next generation solution empowers OEMs and ODMs to incorporate a range of advanced features into their designs while reducing the overall cost, size and weight of the end-product. The company is headquartered in Cambridge UK with a subsidiary office in the Netherlands.