Forefront RF
Superior RF Front-End Solutions for XGen Phones

Modern mobile phones should be capable of operating in over 30 bands, and the number of bands to support is continuously increasing. Every frequency band requires a separate duplex filter. This sheer number of band-specific filters required for increased data speeds and enhanced experiences makes it untenable and complicated for the manufacturer to design mobile devices and other wireless connected systems within the same form factor.

Co-founded by Dr. Leo Laughlin and Julian Hildersley, Forefront RF is a fabless semiconductor company committed to changing the way the RF Front End of global smartphones, wearables, and IoT devices are designed. The research leading to Forefront RF’s solution took shape at the University of Bristol and reduces the complexity of the RF Front-End by eliminating the need for separate duplex filters and associated switches for each band supported by a mobile phone. Forefront RF’s solution reduces the required board space and increases the number of bands that can be supported.

“While lots of attention is given to 5G and mm-Wave, operators still highly rely on the low-frequency bands, below 1GHz, as the primary connection,” says Ronald Wilting, CEO of Forefront RF. “Our solution is focused on covering the full lowfrequency spectrum between 600 and 1000MHz—which includes >20 defined bands — by means of a tunable duplex filter inside a RF Front End module,” he adds. The module includes a wide band Power Amplifier (PA) and wideband Low Noise Amplifier (LNA), and other peripherals required to complete the RF FrontEnd.

The conventional implementation is to use SAW or BAW filters, however, there is no way to tune them. Every new frequency band requires a new filter. Traditional tunable filters don’t have the required out-of-band attenuation and have, therefore, never been an attractive solution. Dr. Leo Laughlin’s invention uses an improved electrical balance duplexer—that overcomes the traditional 3dB circuit loss and is combined with Adaptive Passive Cancellation. This is a technique to cancel the unwanted strong signal from the transmitter at the input of the receiver by adding an inverted version of that signal. It is comparable to the approach used in noise-canceling headphones, but on much higher frequencies. The adaptive part is vital, electrical balance networks require symmetry, and therefore any change in the environment, like the antenna, will require the solution to be tuned.

The FFM61010 RF Front-End module is a multi-chip module that integrates the tunable duplexer, the Power Amplifier, Low Noise Amplifier, and the RF coupler and is controlled by a standard MIPI RFFE interface. Forefront RF has already developed a core tuning algorithm that needs embedding in either the Application Processor or Baseband of the module phone.

The company is still in the development phase and is targeting to start sampling its solution to targeted customers by summer 2023. “We already have the hardware and prototypes in place, along with the algorithm to control the solutions. We have also demonstrated the tunable duplexer in our office on prototypes, on the level we’ll implement it in the product later on. The main effort now is to start the miniaturization process by means of dedicated IC development done together with our design partners,” adds Wilting.

Since its inception, Forefront RF has stayed true to its foundational values and houses a multidisciplinary team that fosters relationships with all its stakeholders. It is headed by experienced leaders and has professionals across the semiconductor and mobile phone industry focusing on marketing and sales management, manufacturing and assembly testing, and the engineering side of things.

With the mobile phone and adjacent markets embracing miniaturization, Forefront RF’s XGen-capable technology will help manufacturers include more features while reducing the cost and size of the device.