Can the F-35 evade modern VHF radars in Russia and China? Technical analysis of stealth capabilities against anti-stealth systems.

The Lockheed Martin F-35 Lightning II is often touted as the most advanced fighter jet of its generation, thanks to its stealth design and sophisticated electronic systems. However, the emergence of new-generation VHF (Very High Frequency) radars, notably deployed by Russia and China, is calling into question the F-35’s ability to operate undetected. These radars, operating at longer wavelengths, could detect stealth aircraft designed primarily to evade short-wave radars. This article examines in detail the detection capabilities of modern VHF radars and assesses the extent to which they compromise the F-35’s stealth.

The principles of F-35 stealth

The F-35 Lightning II is a multi-role fighter aircraft designed around a concept of active and passive stealth. Its reduced radar signature is based on three fundamental technological pillars: airframe geometry, absorbent materials, and equipment integration into the structure.

Aerodynamic shape

The F-35’s airframe is designed with specific angles to reflect radar waves away from their source. Unlike a conventional aircraft, whose curved surfaces reflect the signal in all directions, the F-35 uses straight lines, sharp edges, and sloping panels. The alignment of the leading and trailing edges of the wings, vertical fins, and hatches contributes to this reduction. The air intakes are also curved and concealed to prevent detection of the turbines, which are highly reflective surfaces.

Absorbent materials

The F-35’s outer skin uses a composite made from radar-absorbing materials (RAM). This coating dissipates some of the energy from electromagnetic waves as heat instead of reflecting it. The thickness, composition, and distribution of these materials are optimized for radars operating primarily in the X (8 to 12 GHz) and S (2 to 4 GHz) bands. This choice is based on the fact that these bands are most commonly used by engagement and target tracking radars.

System integration

The F-35’s sensors, weapons and antennas are embedded in the airframe, avoiding the reflection points typical of conventional aircraft. Air-to-air and air-to-ground missiles and guided bombs are housed in internal bays. Even the 25 mm GAU-22/A cannon is hidden behind a hatch. This configuration avoids external pylons, which would significantly increase the radar cross section (RCS).

Limitations against VHF radars

The F-35’s stealth is effective against shortwave radars. However, VHF radars, operating between 30 and 300 MHz (wavelengths of 1 to 10 meters), pose a challenge. At these frequencies, the size of the aircraft is close to the wavelength, which causes resonance phenomena. This increases the probability of detection, as RAM materials and stealth shapes are less effective against these longer waves.

Thus, although the F-35 remains difficult to target accurately, its stealth can be compromised in environments with VHF radars, requiring adapted tactics and mission profiles.

The capabilities of Russian VHF radars

Since the 1990s, Russia has invested in radar systems capable of detecting stealth aircraft designed to evade conventional radars. Particular attention has been paid to systems operating in the VHF (Very High Frequency) band, whose physical characteristics reduce the effectiveness of modern stealth techniques. These radars use wavelengths between 1 and 10 meters (30 to 300 MHz), much higher than those of X-band radars, which changes the behavior of waves when they hit stealth surfaces.

Nebo-M radar system

The Nebo-M (55Zh6M) is a multiband radar complex developed by NNIIRT, designed to operate simultaneously in the VHF, UHF, and L bands. It is a modular system capable of processing and merging data from multiple sensors. The VHF radar carried by the Nebo-M, designated RLM-M, can detect targets at over 300 kilometers, even if they have a radar cross section (RCS) of less than 0.01 m², as is the case with the F-35 on a head-on approach.

This system is designed to detect, track, and transmit coordinates to ground-to-air missile systems such as the S-400. The Nebo-M is mounted on a mobile chassis and can be deployed in a matter of hours, enhancing the flexibility of the detection network.

Rezonans-NE radar

The Rezonans-NE is another Russian long-range radar dedicated to detecting low-radar-signature targets. Fixed and large in size, it uses passive phased array VHF antenna arrays. It is said to be capable of detecting an F-35 or B-2 Spirit at over 400 km and simultaneously tracking more than 500 targets. Its bistatic mode also allows it to detect aircraft flying at very high altitudes.

Detection capability and role in the defense system

Although these radars do not have sufficient resolution to guide missiles with precision, they play a strategic role as early warning sensors. They are used to detect stealth incursions, transmit approximate coordinates to shortwave radars (X-band or C-band), and then enable precise engagement by missile systems. The Russian approach is thus based on a superimposition of complementary sensors, with VHF radar as the first link in an integrated detection chain.

This model challenges the freedom of action of stealth aircraft such as the F-35 in contested environments.

Chinese advances in VHF radar

Faced with the development of Western stealth aircraft such as the F-35, China has launched an aggressive technology policy aimed at strengthening its radar detection capabilities. Beijing is focusing in particular on high-performance VHF systems designed to detect targets with a reduced radar signature in conventional bands. The Chinese approach is based on the systemic integration of these sensors within a network of ground, air and space radars to ensure permanent coverage.

The JY-27A radar

The JY-27A is an AESA (Active Electronically Scanned Array) VHF radar developed by the China Electronics Technology Group Corporation (CETC). Unlike conventional VHF radars with rotating antennas, the JY-27A uses an electronically scanned antenna that allows for very fast response times and better resistance to jamming. Thanks to its active phased array, it can detect air targets at ranges of over 500 kilometers, including those with an RCS of less than 0.01 m², such as the F-35 on a head-on approach.

Its modular panel structure gives it great deployment flexibility, particularly in sensitive areas near the Taiwan Strait. The JY-27A is designed to operate in a network with other radars in different bands (L, S, and X), ensuring multi-band data fusion and increasing the probability of detection.

The SIAR system

The SIAR (Synthetic Impulse and Aperture Radar) is an experimental system that is still poorly documented, but whose first installations have been spotted on militarized islands such as Fiery Cross Reef and Subi Reef in the South China Sea. It is based on the use of synthetic pulses on an extended VHF base, with a clear objective: to render medium-altitude stealth ineffective in areas under constant surveillance.

This system is designed to fill the radar blind spots left by conventional installations, with a focus on long-range initial detection. Once the target has been detected, other means (X-band radars, satellites, drones) are used to carry out precise identification and engage in interception.

A networked approach

Unlike an isolated radar architecture, the Chinese doctrine is based on multi-level integration, including VHF radars in a larger system. The information collected is merged via automated command centers, linked by fiber optics and satellite transmissions. This network includes:

• ground-based radars of all bands;
• airborne radars (such as the KJ-500);
• orbital sensors.

This allows the resolution limitations of VHF radars to be overcome through functional redundancy. In practice, an F-35 entering Chinese airspace is statistically more likely to be detected than in an isolated environment.

China is thus building a detection ecosystem capable of challenging the operational advantage of stealth aircraft in high-intensity warfare.

The limits of stealth against VHF radars

The F-35 Lightning II, like other stealth aircraft, is designed to reduce its radar cross section (RCS) by manipulating geometry, materials, and equipment integration. These techniques are effective against high-frequency radars (X, S, or Ku bands), which are widely used in Western defense systems. However, they have significant limitations against VHF radars due to the very nature of electromagnetic waves in this frequency range.

Effect of long wavelengths

VHF waves, between 30 MHz and 300 MHz (wavelengths between 1 and 10 meters), interact differently with aeronautical structures. At these frequencies, stealth techniques based on angled edges and RAM coatings become less effective. This is because the wavelength becomes comparable to certain dimensions of the aircraft’s airframe (wings, tail, hatches), causing electromagnetic resonance phenomena. This generates increased radar reflection, even for objects whose shape has been designed to minimize this response.

Limited resolution, detection possible

Although VHF radars have poor angular resolution and location accuracy compared to X-band radars, they are still capable of detecting the presence of a stealth target. Their low accuracy does not prevent them from providing a rough location sufficient to alert a defense network. Simply detecting an F-35 in a given volume of airspace allows other more accurate sensors to be focused on it, or a defensive response to be prepared.

Role in multi-layer architectures

VHF radars are not designed to guide missiles with precision. However, they play a strategic role in multi-layered defense architectures. In Russia and China, these radars are connected to command centers that use the initial detection to activate other medium- or high-frequency radars (L, S, X bands) and allocate fire resources (surface-to-air missiles, interceptors).

This ability to trigger a chain reaction based on approximate detection makes VHF detection a key element of early warning. Stealth aircraft do not disappear, they simply become more difficult to engage. However, this advantage is greatly reduced in a dense and digitally coordinated environment, forcing the F-35 to adapt its mission profiles and integrate specific countermeasures.

Thus, even without precise location, the F-35’s stealth loses its operational relevance when the theater is equipped with interconnected VHF radars supported by more accurate confirmation means.

Implications for F-35 operations

The growing presence of VHF radars in Russian and Chinese military systems is profoundly changing the conditions of use of the F-35 in contested areas. Although this fighter aircraft retains a low radar signature in most frequency bands, it can no longer rely exclusively on passive stealth to ensure its survival. This development requires tactical, technical, and doctrinal adaptations, particularly in high-intensity air warfare scenarios.

Mission planning

In theaters where VHF radars are operational, route planning becomes a delicate operation. It is necessary to avoid anticipated detection cones, which requires longer routes, lower altitudes, or flying through less monitored air corridors. Each change increases fuel consumption, limits time in the area of operations, and complicates synchronization with other platforms. In addition, because radar installations are mobile or concealed, real-time intelligence becomes crucial.

Use of electronic warfare

To compensate for passive detection, the F-35 incorporates advanced electronic warfare systems, such as the AN/ASQ-239, capable of detecting radar emissions, classifying them, and generating countermeasures. However, VHF radars, due to their power and beam width, are more difficult to deceive or jam than shortwave radars. Countermeasures must therefore be deployed in a targeted manner, sometimes with the assistance of a specialized electronic warfare aircraft (such as the EA-18G Growler).

Cross-platform coordination

In a sensor-saturated environment, the F-35 cannot operate in isolation. It must be integrated into an interoperability network comprising ISR (intelligence, surveillance, reconnaissance) drones, electronic warfare aircraft, and airborne command platforms (AWACS). Tactical data sharing architecture, such as Link 16 or MADL (Multifunction Advanced Data Link), is becoming essential for adapting maneuvers to radar threats in real time.

Reduced freedom of action

All these constraints lead to a reduction in freedom of action in areas with high radar density. The F-35 remains difficult to engage, but its stealth characteristics no longer guarantee impunity. Pilots must operate with reduced maneuverability, sometimes in tactical subordination to enemy ground-to-air systems. This reality is forcing air forces to rethink their engagement concepts, favoring coordinated strikes and saturation effects rather than isolated and discreet entries.

The integration of VHF radars into intelligent networks is thus transforming the context in which the F-35 is used, making a multi-domain approach essential to maintain air initiative.

The development and deployment of modern VHF radars by Russia and China are calling into question the effectiveness of the F-35’s stealth capabilities.

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