Level Measurement · Radar Level Meters
Radar level meter in 80 GHz, low-frequency and guided-wave series for tanks, silos, rivers and pressurised vessels, with spans from 10 m to 80 m.
MIK-RD908 (3 models) ·
Radar is the level technology that works when the surface cannot be seen. It measures with microwaves rather than with sound, so vapour, steam, a temperature layer, dust and foam that would disturb an acoustic pulse pass through it largely unaffected. That is why it is the answer for a hot process vessel, a dusty silo and an outdoor river gauge, and why it is normally the more expensive of the two non-contact options.
The range behind this page carries that principle across three different antenna arrangements, because what changes between duties is not the idea but how the signal is delivered.
The high-frequency series radiates at 80 GHz, which is a short enough wavelength to resolve small targets and to be focused into a narrow beam. That combination is what makes it usable on a tall silo where the surface is far away, and on a vessel with an obstruction close to the antenna which a wider beam would strike and read instead of the surface. The narrowest beam in the range is given as 3°, and one model reaches a blanking distance of 8 cm, which is what allows measurement to continue close beneath the instrument.
The low-frequency series uses far larger antennas for the same job and is described for liquids in tanks, including strongly corrosive ones where the antenna material has to be chosen against the medium. The guided-wave series abandons free-space radiation altogether: the signal runs along a rod or a cable that reaches down into the liquid, so the path is fixed and the problems that afflict a beam in open air disappear with the beam. It is the series that reaches the highest process temperature in the range.
The first question is not range but path. A free-space instrument needs a clear line from its antenna to the surface, so if there is foam, heavy condensation, a narrow vessel, an agitator in the beam or a process hot enough to trouble the antenna, the answer is the guided-wave series. Where the path is clear, the choice between high and low frequency is mostly one of distance and target size: the high-frequency series resolves smaller targets and can be aimed more precisely, which matters on a tall or obstructed vessel, and the low-frequency series is the simpler route where the surface is close and the beam has room.
Range and accuracy then narrow the model rather than the series, and both are given per model in the material because the antenna and the medium change what is achievable. The general description also claims an accuracy of 0.1 %, which is a different figure from the per-model millimetre values and is not reconciled with them; the per-model figures are the ones to work from.
Pressure and temperature decide the model more often than the range does. Across the range, pressure spans from a reference to atmosphere on the models intended for open vessels up to 4 MPa on those built for pressurised service, and temperature from ambient on the 80 GHz models to 250 °C on the guided-wave series. A process vessel with both pressure and temperature on it therefore has a shorter list of candidates than its level range alone would suggest.
The wetted parts follow the medium. Antennas are offered in rod, horn, cable and sealed corrosion-resistant forms, and the flange and horn on the high-frequency series are stainless steel. Where the medium is aggressive, the antenna material and the sealing around it are what decide whether the instrument survives, and the material offers a corrosion-resistant antenna form for exactly that case.
Two errors account for most radar installations that do not work, and the material states both. The first is a level that rises into the blanking distance: close to the antenna the instrument cannot separate its own transmission from the returning echo, so the highest level the vessel may reach has to stay below that band. The second is an obstruction inside the beam. The signal is radiated in a cone, and anything within that cone - a filling pipe, a ladder, a heating coil, the vessel wall on a narrow vessel - returns an echo that may arrive before the surface echo does. The material’s instruction is accordingly to keep the beam clear and to set the antenna face square to the surface, with the reference plane taken at the underside of the thread or the flange sealing face.
The limitations belong to the technology rather than to the range. Radar measures to the first strong reflection in its beam, so a foam layer can be read as the surface if it is dense enough, and a very low dielectric medium reflects weakly and may return too little to resolve. Neither is a fault - they are the conditions under which another principle is the better answer, which is why the boundary between radar and ultrasonic is drawn by the atmosphere above the medium and the boundary between radar and a wetted probe is drawn by what is in the vessel.
The material also leaves a number of figures unsettled, and they are listed rather than glossed. The protection rating varies by model, the supply voltage is stated for two models only, the process temperature is absent for most of the low-frequency and high-frequency series, and one model is given two different ranges in different places in the same document. Those are recorded as questions rather than resolved here, because settling them by inference would put an unverified figure on a specification sheet.
The items that fix the answer are the vessel height, diameter and the highest and lowest levels; the medium and whether it is a liquid, a powder or a solid; the vapour, dust, foam and condensation above the surface; the process pressure and temperature; what is inside the vessel and how much clearance the antenna has to the wall; the process connection the vessel provides; the outputs required and what will read them; and whether the reading has to be visible at the vessel or only as a signal. A vessel drawing with pressure and temperature marked on it answers most of these, and it is the most useful single item in an enquiry. Quantity, destination port and required delivery date complete it.
Every value below is taken from source documentation. Where a parameter is not stated in the available material it is marked as information required rather than estimated.
| Frequency | 80 GHz frequency-modulated continuous wave with an 11 mm wavelength on the high-frequency series; 500 MHz to 1.8 GHz on the guided-wave seriesStandard |
|---|---|
| Range | 0 to 10 m through to 0 to 80 m across the range, according to modelStandard |
| Accuracy | Per model, from ±5 mm on the shortest spans through ±10 mm at 20 m, ±20 mm at 30 m and ±30 mm at a 70 m span; a general description in the same material also claims an accuracy of 0.1 %, which is a different figure from the per-model values and is not reconciled with themInformation required |
| Beam angle | 3.8°, 5.8° and 8° on one 80 GHz model, and 3° to 10° in the general description, with the narrowest given as 3°Standard |
| Blanking distance | 0.08 m on one 80 GHz model and ≤0.4 m on another; not stated for the remaining modelsInformation required |
| Resolution and repeatability | A millimetre resolution is claimed in the general description and no repeatability figure is given for any modelInformation required |
| Process pressure | -0.1 to 0.3 MPa on the atmosphere-referenced models, up to -0.1 to 4 MPa on the models built for pressure, and -0.1 to 0.6 MPa on one low-frequency modelStandard |
|---|---|
| Process temperature | -40 to 250 °C on the guided-wave series, -40 to 200 °C on one guided-wave model, -20 to 80 °C on one 80 GHz model and -20 to 60 °C on another; the remaining models do not state a process temperatureInformation required |
| Medium | Liquids, corrosive liquids, volatile liquids, steam, solids and powders, according to model; the high-frequency series is described as covering strong dust and steam, and the guided-wave series as covering pressurised and volatile liquidsStandard |
| Process connection | Thread, flange, universal flange and a turned-edge flange, according to model; one low-frequency model uses a DN150 PN16 flangeStandard |
| Output | 4-20 mA with HART on the low-frequency and guided-wave series; 4-20 mA with HART and RS-485 with Modbus on the high-frequency seriesStandard |
|---|---|
| Supply | 24 V DC where stated; the material gives 6 to 24 V DC against one RS-485 output and 24 V DC against one 4-20 mA output, and does not state a supply for the remaining modelsInformation required |
| Display | A four-digit liquid-crystal display on the high-frequency seriesStandard |
| Bluetooth | Offered on one 80 GHz model and on the wireless modelOptional |
| Wireless reporting | One model is described as reporting to a cloud service, with a stated average power, a transmission interval and a period of included dataOptional |
| Ingress protection | IP65 on one model, IP67 on most, and IP68 on a liquid-duty form; the material states that the figure varies by modelInformation required |
|---|---|
| Housing | A dual-chamber housing; stainless steel on the guided-wave series, with a sealed antenna and a 304 stainless flange and horn on the high-frequency seriesStandard |
| Antenna types | Rod, horn, cable and sealed anti-corrosion antennas, according to seriesStandard |
| Weight and flange dimensions | Not stated for the larger modelsInformation required |
| Reference plane | The underside of the thread or the sealing face of the flangeStandard |
|---|---|
| Blanking | The highest level must not enter the blanking distanceStandard |
| Beam clearance | No obstruction may lie inside the beam between the antenna and the surfaceStandard |
| Orientation | The antenna face square to the surfaceStandard |
| Outdoor installation | One installation drawing in the material shows a bracket-mounted unit with a solar panel and a distribution boxOptional |
| Scope | Additional forms supplied in November 2026 for this product type. Figures below are from that batch; where they differ from the rows above, both are recorded rather than merged.Standard |
|---|---|
| Range | 0 to 10 m and 0 to 20 mStandard |
| Output | 4-20 mA, RS-485/Modbus and HARTStandard |
| Supply | 24 V DC, with 220 V AC versionsStandard |
| Process temperature | -40 to 200 C, with high-temperature versions to 1000 CStandard |
| Process connection | Flanged DN80 to DN150 and threaded versionsStandard |
| Wetted material | 304 stainless body with a PTFE lensStandard |
| Ingress protection | IP67Standard |
| Model | Configuration | Key ranges | Availability |
|---|---|---|---|
| MIK-RD908 | 80 GHz model described for rivers, lakes and shallows | 0 to 30 m; ±5 mm at 10 m and ±10 mm at 30 m; atmospheric pressure; IP67; thread, bracket or flange | |
| MIK-RD901 | 80 GHz model for strongly corrosive liquids | 0 to 10 m; ±5 mm to 5 m and ±10 mm at 10 m; -0.1 to 0.3 MPa; IP67; thread or flange | |
| MIK-RD902 | 80 GHz model for high temperature and pressure with slight corrosion | 0 to 30 m; ±5 mm to 5 m; -0.1 to 4.0 MPa; IP67; thread or flange | |
| MIK-RD903 | 80 GHz model for solids and heavy dust | 0 to 70 m; ±20 mm at 30 m and ±30 mm at 70 m; -0.1 to 0.3 MPa on a universal flange and -0.1 to 4 MPa on a flat flange; IP67 | |
| MIK-RD904 | 80 GHz model for condensation and process vessels | 0 to 80 m; ±25 mm; -0.1 to 0.3 MPa; IP67; universal flange | |
| MIK-RD902T | 80 GHz model for corrosive liquids, steam and volatile liquids | 0 to 20 m; ±10 mm; -0.1 to 2.0 MPa; the material records that the protection and connection fields are transposed in its own table for this model | |
| 80G-WSR450 | 80 GHz model for stirred tanks, steam and solids | 5 m, 10 m, 15 m and 20 m ranges; blanking ≤0.4 m; ±10 mm at a damping factor of 2; beam angle 3.8°, 5.8° or 8°; IP65; -20 to 80 °C | |
| MIK-WSR550 | 80 GHz wireless model for tanks, solids and dust | 0 to 10 m as standard with 60 m available; blanking 0.08 m; Bluetooth; the nameplate gives 24 V DC, IP67 and -20 to 60 °C | |
| MIK-RD801 | Low-frequency model for liquids and mildly corrosive liquids | 0 to 20 m; ±10 mm at 5 m and ±20 mm at 20 m; rod antenna in PP or PTFE; -0.1 to 0.3 MPa | |
| MIK-RD802 | Low-frequency model for strongly corrosive liquids | 0 to 20 m; ±10 mm at 5 m, ±15 mm at 20 m and ±20 mm at 35 m; PTFE rod antenna; -0.1 to 1.6 MPa | |
| MIK-RD803 | Low-frequency model for pressurised and volatile liquids | 0 to 35 m; ±10 mm at 5 m, ±15 mm at 20 m and ±20 mm at 35 m; horn antenna; -0.1 to 4 MPa; turned-edge flange | |
| MIK-RD803T | Low-frequency model for corrosive and volatile liquids | 0 to 20 m; ±15 mm at 10 m and ±20 mm at 20 m; sealed corrosion-resistant antenna; -0.1 to 0.6 MPa; DN150 PN16 flange | |
| MIK-RD701 | Guided-wave model for liquids and solid powders | 0 to 30 m; 500 MHz to 1.8 GHz; ±5 mm at 2 m, ±10 mm at 10 m, ±20 mm at 20 m and ±25 mm at 30 m; rod or single-cable antenna; -0.1 to 4 MPa; -40 to 250 °C | |
| MIK-RD702 | Guided-wave model for liquids and strongly corrosive liquids | 0 to 20 m; 500 MHz to 1.8 GHz; ±5 mm at 2 m and ±10 mm at 10 m; rod or PTFE cable antenna; -0.1 to 0.3 MPa; -40 to 200 °C |
Certifications are only published once a certificate copy can be produced, so this section is deliberately empty rather than populated with assumed approvals. Tell us which approvals your application requires and we will confirm what is available for this instrument.
The following are required for a complete specification but are not stated in the documentation supplied to us. They are listed rather than estimated:
Because the antenna and the frequency have to change with the duty, and no single arrangement covers all of them. The high-frequency series works in a free space above the medium and is the one for a tall silo, a dusty bin or a vessel with a narrow clearance, since a narrow beam can be aimed past an obstruction. The low-frequency series uses larger antennas and suits liquids in tanks where the extra reach through vapour is an advantage. The guided-wave series runs a wave along a rod or a cable into the liquid, which is the answer where a free-space beam would be disturbed or where the process runs hot.
The vessel and the medium, in that order. The vessel gives the span, the height available above the surface, the diameter, and what is inside it - because the beam must reach the surface without touching anything on the way. The medium gives the antenna material and whether a free-space beam is viable at all, since a guided-wave model is the alternative where it is not. Then the process pressure and temperature, which decide the model rather than the series, and the process connection the vessel provides. A vessel drawing with the pressure and temperature on it settles most of the choice before the enquiry is sent.
Because the material gives it per model: IP65 on one, IP67 on most and IP68 on a liquid-duty form, with a note that the figure varies. That is a genuine difference rather than a documentation gap - the models differ in housing and in how the antenna is sealed - but it means the rating has to be read off the model being ordered rather than taken from the series. The same applies to the supply voltage, which the material states for only two models across the range, and to the process temperature, which it gives for the guided-wave models and two of the high-frequency models.
When a free-space beam cannot be trusted. A beam in open air is disturbed by turbulence, by a foam layer, by heavy condensation and by the geometry of the vessel, and it needs a clear path from the antenna to the surface. A guided-wave instrument sends its signal along a rod or a cable that reaches into the liquid, so the path is fixed and those problems disappear. It also reaches higher temperatures more easily, with one model rated to 250 °C. The trade is that the probe is wetted and has to be compatible with the medium, and that it needs the vessel to accept a probe rather than only a flange.
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