# Agilent E4991A RF Impedance/Material Analyzer (Pre-Owned) # Agilent E4991A RF Impedance/Material Analyzer (Pre-Owned) ## Key Features At A Glance - RF impedance/material analyzer covering 1 MHz to 3 GHz with 1 mHz source frequency resolution - Impedance measurement range of 130 mO to 20 kO at the 7-mm test head connector - Measures |Z|, |Y|, Ls, Lp, Cs, Cp, Rs, Rp, X, G, B, D, Q and reflection-coefficient parameters - Optional permittivity and permeability material measurement (Option E4991A-002 with 16453A/16454A fixtures) - Optional DC bias to +/-40 V and 100 uA to 50 mA for biased component characterization (Option E4991A-001) - GPIB (IEEE 488.2), LAN (10/100 Base-T), USB, and IEEE 1284 parallel interfaces - Equivalent circuit analysis with 3- and 4-component models plus frequency-characteristic simulation - 8.4-inch color LCD, up to 801 measurement points, and segment sweep of up to 16 segments The Agilent E4991A is an RF impedance/material analyzer that characterizes components and materials across a frequency range of 1 MHz to 3 GHz. It resolves a broad set of impedance parameters from a 7-mm connector at its test head, including |Z|, |Y|, series and parallel inductance (Ls, Lp), series and parallel capacitance (Cs, Cp), resistance (Rs, Rp), reactance (X), conductance (G), susceptance (B), dissipation factor (D), quality factor (Q), the impedance and admittance phase angles, and the reflection coefficient and its components. An impedance analyzer applies a known RF stimulus to a device under test and resolves the resulting voltage and current into the component's complex impedance, letting an engineer extract values such as inductance, capacitance, and equivalent series resistance at the frequency where the part actually operates. The E4991A extends this approach to material characterization: when configured with the material measurement option it derives permittivity parameters (|er|, er', er", tand) and permeability parameters (|ur|, ur', ur", tand) from a material under test. ValueTronics stocks and holds its own test-and-measurement inventory in a 20,000 sq ft secure warehouse at 1675 Cambridge Drive in Elgin, Illinois. Because we hold the equipment ourselves, every pre-owned unit is inspected and functionally verified in-house before it ships, while new units leave our warehouse factory-sealed exactly as received from the manufacturer. ## Brand Heritage Agilent Technologies was formed in 1999 as a spin-off of Hewlett-Packard's test and measurement business. In 2014, Agilent's electronic measurement operations were established as Keysight Technologies, which continues to support instruments originally introduced under the Agilent brand. ## Accessories Supplied - Agilent E4991A impedance/material analyzer (main unit) - Test head - Agilent 16195B 7-mm calibration kit - Torque wrench - E4991A recovery disk - Power cable - CD-ROM (English/Japanese PDF manuals) ## Product Core & Specifications Specification Value Measurement Parameters and Range Impedance parameters |Z|, |Y|, Ls, Lp, Cs, Cp, Rs(R), Rp, X, G, B, D, Q, θz, θy, |Γ|, Γx, Γy, θγ Material parameters (Option E4991A-002) Permittivity: |εr|, εr', εr", tanδ; Permeability: |μr|, μr', μr", tanδ Measurement range (|Z|) 130 mΩ to 20 kΩ (Frequency = 1 MHz, point averaging factor ≥ 8, oscillator level = –3 dBm; = –13 dBm; or = –23 dBm, measurement accuracy ≤ ±10%) Source Characteristics — Frequency Range 1 MHz to 3 GHz Resolution 1 mHz Accuracy (without Option E4991A-1D5) ±10 ppm (23 °C ±5 °C); ±20 ppm (5 °C to 40 °C) Accuracy (with Option E4991A-1D5) ±1 ppm (5 °C to 40 °C) Stability (with Option E4991A-1D5) ±0.5 ppm/year (5 °C to 40 °C) (typical) Source Characteristics — Oscillator Level Power range (50 Ω load at test port) –40 dBm to 1 dBm (frequency ≤ 1 GHz); –40 dBm to 0 dBm (frequency > 1 GHz) Current range (short at test port) 0.0894 mArms to 10 mArms (frequency ≤ 1 GHz); 0.0894 mArms to 8.94 mArms (frequency > 1 GHz) Voltage range (open at test port) 4.47 mVrms to 502 mVrms (frequency ≤ 1 GHz); 4.47 mVrms to 447 mVrms (frequency > 1 GHz) Resolution 0.1 dB Power accuracy (frequency ≤ 1 GHz) ±2 dB (23 °C ±5 °C); ±4 dB (5 °C to 40 °C) Power accuracy (frequency > 1 GHz) ±3 dB (23 °C ±5 °C); ±5 dB (5 °C to 40 °C) Output impedance 50 Ω (nominal) DC Bias (Option E4991A-001) DC voltage bias range 0 to ±40 V DC voltage bias resolution 1 mV DC voltage bias accuracy ±{0.1% + 6 mV + (Idc\[mA\] x 20 Ω)\[mV\]} (23 °C ±5 °C); ±{0.2% + 12 mV + (Idc\[mA\] x 40 Ω)\[mV\]} (5 °C to 40 °C) DC current bias range 100 µA to 50 mA, –100 µA to –50 mA DC current bias resolution 10 µA DC current bias accuracy ±{0.2% + 20 µA + (Vdc\[V\] /10 kΩ)\[mA\]} (23 °C ±5 °C); ±{0.4% + 40 µA + (Vdc\[V\] /5 kΩ)\[mA\]} (5 °C to 40 °C) Sweep Characteristics Sweep parameters Frequency, oscillator level (power, voltage, current), DC bias voltage, DC bias current Sweep range setup Start/stop or center/span Sweep types Frequency sweep: linear, log, segment; Other parameters sweep: linear, log Sweep mode Continuous, single Number of measurement points 2 to 801 Delay time range 0 to 30 sec (resolution 1 msec) Number of segments (segment sweep) 1 to 16 Trigger Trigger mode Internal, external (external trigger input connector), bus (GPIB), manual (front key) Averaging Types Sweep-to-sweep averaging, point averaging Sweep-to-sweep averaging range 1 to 999 (integer) Point averaging range 1 to 100 (integer) Display LCD type/size Color LCD, 8.4 inch (21.3 cm) Resolution 640 (horizontal) × 480 (vertical) Number of traces Data trace: 3 scalar traces + 2 complex traces (maximum); Memory trace: 3 scalar traces + 2 complex traces (maximum) Marker Main marker One for each trace (marker 1) Sub marker Seven for each trace (marker 2 to marker 8) Reference marker One for each trace (marker R) Mass Storage Built-in flexible disk drive 3.5 inch, 720 KByte or 1.44 MByte, DOS format Hard disk drive 2 GByte (minimum) Interface GPIB IEEE 488.1-1987, IEEE 488.2-1987 Printer parallel port IEEE 1284 Centronics, 25-pin D-sub connector, female LAN interface 10 Base-T or 100 Base-TX (automatically switched), Ethertwist, RJ45 connector, TCP/IP, FTP USB port USB 1.1, Standard USB A, female Rear Panel Connectors External reference signal input 10 MHz ±10 ppm (typical), level 0 dBm to +6 dBm (typical), 50 Ω (nominal), BNC female Internal reference signal output 10 MHz (nominal), level +2 dBm (nominal), 50 Ω (nominal), BNC female High stability frequency reference output (Option E4991A-1D5) 10 MHz (nominal), level +2 dBm (nominal), 50 Ω (nominal), BNC female Measurement Terminal (At Test Head) Connector type 7-mm connector General Characteristics Operating temperature 5 °C to 40 °C Operating humidity Flexible disk drive non-operating: 15% to 90% RH; operating: 20% to 80% RH (at wet bulb temperature ≤ 29 °C, without condensation) Operating altitude 0 m to 2,000 m (0 feet to 6,561 feet) Operating vibration 0.5 G maximum, 5 Hz to 500 Hz Warm-up time 30 minutes Storage temperature –20 °C to +60 °C Storage humidity 15% to 90% RH (at wet bulb temperature ≤ 45 °C, without condensation) Storage altitude 0 m to 4,572 m (0 feet to 15,000 feet) Storage vibration 1 G maximum, 5 Hz to 500 Hz Power requirements 90 V to 132 V, or 198 V to 264 V (automatically switched), 47 Hz to 63 Hz, 350 VA maximum Weight Main unit: 17 kg (nominal); Test head: 1 kg (nominal) Other Specifications EMC European Council Directive 89/336/EEC; IEC 61326-1:1997+A1; CISPR 11:1990 / EN 55011:1991 Group 1, Class A; AS/NZS 2064.1/2 Group 1, Class A Safety European Council Directive 73/23/EEC; IEC 61010-1:1990+A1+A2 / EN 61010-1:1993+A2, Installation Category II, Pollution Degree 2, Indoor Use; IEC60825-1:1994 Class 1 LED Product; CAN/CSA C22.2 No. 1010.1-92 > **Important:** Setting an oscillator level above 0 dBm (447 mV, 8.94 mA) is possible at frequencies above 1 GHz, but the characteristics at this setting are not guaranteed. > **Important:** Material measurement (Option E4991A-002) requires the Agilent 16453A or 16454A test fixture (1 MHz to 1 GHz, typical); these test fixtures are not part of the standard furnished accessories and must be ordered separately. > **Important:** The supplied CD-ROM includes an operation manual, an installation and quick start guide, and a programming manual. A service manual is not included. ## About this Pre-Owned unit This pre-owned unit is inspected and functionally verified in-house before it ships and is backed by our pre-owned warranty. To confirm its exact condition, firmware revision, installed options, or included accessories for your application before ordering, contact our Test Architects. - Warranty included - Functional verification included - Standard Calibration Upgrade Options: No Calibration Required, NIST Traceable, Z540.1 or ISO 17025 with Data, Z540.3 Guardbanding with Data. - Note that unnecessary accessories may not be included (contact Test Architect to confirm). ValueTronics supplies both new and used test and measurement equipment. New units ship factory-sealed, exactly as received from the manufacturer; every used unit is inspected and functionally verified in-house at our 20,000 sq ft secure facility in Elgin, Illinois before it ships. Our Test Architects can help you select the condition, calibration, and configuration that fit your application. **Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.** ## Details - **Price:** 0.0 USD - 1330.0 USD - **Vendor:** Agilent - **Type:** Impedance Analyzer - **Tags:** Agilent, Agilent Keysight, Agilent Technologies, Analyzers, E4991, E4991A, Impedance, Impedance Analyzer, Inc., Keysight, Keysight Technologies, Manufacturers, Model 4991, Pre-Owned, product_manual_group_1, Product_used ## Variants | Variant | Price | Available | |---------|-------|-----------| | None | 0.00 USD | In stock | | NIST Traceable | 700.00 USD | In stock | | NIST Traceable with Full Data | 1050.00 USD | In stock | | ISO IEC 17025 Accredited | 1330.00 USD | In stock | ## Images - E4991A Keysight Agilent Impedance Analyzer --- > Source: [ValueTronics](https://valuetronics.com/products/e4991a-agilent-impedance-analyzer-used) > Updated: 2026-06-02