Agilent Scanning Microwave Microscope Mode - Application Note 5989-8818EN c20141205 [6] free download

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Keysight Technologies Scanning Microwave Microscope Mode Application Note Introduction Measuring electromagnetic properties of materials can provide insight into applications in many areas of science and technology, and increasingly, these properties need to be evaluated at the nanometer scale. Since electromagnetic properties, such as the dielectric constant, are ultimately related to a material's molecular structure, correlating the detailed physical structure of a material with its electromagnetic properties is frequently more valuable than the knowledge of either alone. Scanning Microwave Microscope (SMM) Mode is a new Scanning Probe Microscope (SPM) that combines the electromagnetic measurement capabilities of a microwave vector network analyzer (VNA) with the nanometer-resolution and Angstrom-scale positioning capabilities of an Atomic Force Microscope (AFM). The Keysight Technologies, Inc. VNAs are mature, highly sophisticated characterization instruments that make extremely accurate, calibrated measurements of complex-valued ratios on electromagnetic signals. The ratios are and The incident signal is generated and controlled inside the VNA; as a result, the ratios R and T are not merely relative, but referenced to the well-known, accurately quantiied incident signal. This measurement capability, delivered to the apex of an AFM tip makes the SMM the only SPM in its class, enabling calibrated, traceable measurements of electrical properties such as impedance and capacitance, with the high spatial resolution that is the hallmark of a well-designed, well-constructed AFM. Microwave Vector Network Analyzer The SMM uses Keysight's VNA microwave vector network analyzer (Figure 1).1 Like all network analyzers, this VNA is a stimulus-response instrument, optimized for accurate and repeatable measurement of the response of a network or a device under test (DUT) to a known stimulus signal. This is in contradistinction to instruments such as the spectrum analyzer, which are usually conigured as a receiver (only) of an unknown signal, and which do not include a source for a stimulus to be applied to the DUT. A VNA has two operational modes: transmission and relection. In the relection (alternatively, transmission) mode, the VNA measures the magnitude and phase characteristics of the DUT by comparing the signal that relects off (alternatively, transmits through) the device with the stimulus signal.2 Each mode enables measurement of several useful parameters. In the relection mode, the VNA can measure (among other things) the impedance of the DUT.3 Scanning Impedance Figure 1. Keysight's VNA microwave vector Microscopy is a major application of the SMM. network analyzer (top) and 5500 AFM (bottom). 03 | Keysight | Scanning Microwave Microscope Mode