Two Antennas to Design with Electromagnetic Simulation
The fundamental goal in cellular and network wireless development is maximizing antenna performance while minimizing antenna size. To achieve this goal, the number of antenna array elements has increased along with the complexity of broadband networks. Highly accurate simulation programs are required for antenna designs and tests. The design software should simulate the antenna in realistic surroundings, including the phone components, surrounding structures, and even the human hand and head.
Compliance testing should also be performed, such as specific absorption ratio (SAR) and hearing aid compatibility (HAC). Below are two examples of types of antennas with design challenges that simulation programs can help solve. More examples can be found on Keysight’s EM Applications Page.
1. Multi-Band Planar Array Antenna
Multi-band planar array antennas order elements in a matrix array on a single plane. They have phased-array beam steering applications where each element in the array gets its own phase shifter. The phase shifters use constructive/destructive interference to control the beam direction of an RF signal.
Antennas such as these with a large effective area become more challenging when the antenna is used for multiple bands. The field solver required to handle the capacity and speed is a design challenge for many engineers.
One approach to this challenge is to divide the EM problem into small “sub-cells” that are integrated individually without carrying out an EM simulation at the full structure level. However, the coupling between the sub-cells will not be accounted for, but this can be enough for most multi-band planar array antenna designs.
Figure 1: Using Keysight’s Momentum 3D Planar EM Simulator, you can design and simulate an entire multi-band planar array antenna for communication and radar applications
2. 8x16 Patch Array Antenna
Patch array antennas are low-profile antennas that also have potential applications in beam steering technology as well and may play a role in 5G technology to improve gain and bandwidth where space is limited. To create the desired directive radiation patterns, designers arrange multiple antennas so that their coexisting wave patterns add constructively or destructively in a specific formation.
The main lobe antenna can be steered by changing the phase of excitations at each array element. Depending on the number of array elements and the complexity of the feeder network, the simulation of a patch array antenna can be quite challenging.
Although simulation time and speed are mostly related to the problem size, another effect on simulation time is the frequency bandwidth. A good simulation program uses a single simulation to produce a wide band simulation result without needing frequency sweeping.
Figure 2: The Keysight EMPro FDTD simulation engine can handle an 8x16 patch array antenna because it produces a wide band simulation result with a single simulation. No frequency sweeping is necessary.
These are two of many prevalent electromagnetic simulation applications of ADS and EMPro that can be found on Keysight’s EM Applications Page.