Follow the steps given at below URL to create avd for Galaxy S4 smartphone. S4 and and xperia z have same screen size (5 inch) and same resolution 1080x1920.
http://developer.sonymobile.com/knowledge-base/sony-add-on-sdk/install-the-sony-add-on-sdk/
Please note that you must also install 'Sony DeviceProfiles' under Extras within the SDK Manager, as well as 'Sony Add-On SDK'.
To exactly match the emulator, clone xperia z from "device definition" tab and chose hardware button to create user defined device and create avd from this new device.
Don't forget to check "Use host GPU emulation" option for avd also keep in mind that your system must have graphics card (GPU) installed in it.
