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Slot Patch Antenna Design
 526.3 Improved Design Methods, 282 References, 283 6 Microstrip Antennas 285 61 Microstrip Antenna Patterns, 287 62 Microstrip Patch Bandwidth and SurfaceWave Ef ciency, 293 63 Rectangular Microstrip Patch Antenna, 299 64 QuarterWave Patch Antenna, 310 65 Circular Microstrip Patch, 313 66 Circularly Polarized Patch Antennas, 316.
 Radiating patch is a very effective method for achieving a wide bandwidth. Several Uslot patch antennas has been reported recently to improve bandwidth810. To enhance the bandwidth we can increase the substrate thickness. However the size of an antenna is an important consideration in the design of patch antenna. The design of circular.
Application Project: Designing A SlotCoupled Patch Antenna Array With A Corporate Feed Network Using EM.Picasso 
Objective: In this project, we will build and analyze a 16element slotcoupled patch antenna array with a microstrip corporate feed network. 
Concepts/Features:

Minimum Version Required: All versions 
' Download Link: None 
Another excellent directional gain antenna is the phased array, which is a group of dipoles or equivalent antennas (patches, slot, etc.) mounted in a rectangular array. Typical arrays might be four.
Introduction
EM.Picasso can be used to analyze large and fairly complex multilayer planar structures. In this application note, we will show how to use EM.Picasso to design a 4 × 4 slotcoupled patch antenna array with a microstrip corporate feed network. The design process involves three steps: design of the slotcouple patch element, design of the power divider, and finally, construction of the 16element array. The first two steps are the subject of two of EM.Picasso's tutorial lessons.
Designing the Patch Radiating Element
The operating frequency of the patch array is f = 2.4GHz. At this frequency, the freespace wavelength is λ_{0} = 125mm. The patch radiators will be spaced at half freespace wavelength: S_{x} = S_{y} = λ_{0}/2 = 62.5mm. The design of the slotcoupled patch antenna is described in detail in EM.Picasso Tutorial Lesson 7: Designing A SlotCoupled Patch Antenna. The substrate consists of two finitethickness dielectric layers with ε_{r} = 3.38, σ = 0, separated by a perfect electric conductor (PEC) ground plane of infinite lateral extents. The table below summarizes the substrate stackup's layer hierarchy:
Substrate Object Label  Substrate Object Type  Function  Material  Thickness 

THS  HalfSpace Medium  Top Substrate Termination  Vacuum  Infinite 
PEC_1  PEC Trace  Patch Plane  PEC  0 
Layer_1  Substrate Layer  Patch Substrate  ROGER RO4003C  2mm 
PMC_1  Slot Trace  Slot Plane  PMC  0 
Layer_2  Substrate Layer  Feed Substrate  ROGER RO4003C  0.787mm 
PEC_2  PEC Trace  Microstrip Feed Plane  PEC  0 
BHS  HalfSpace Medium  Bottom Substrate Termination  Vacuum  Infinite 
The design variables in this problem include the side dimensions of the square patch radiator, length and width of the coupling slot and the length of the open microstrip stub extended beyond the coupling slot. The width of the mircostrip feed line is chosen to be w_{f} = 2.4mm to yield a characteristic impedance of Z_{0} = 50Ω.
Design Variable Name  Optimal value 

patch_len  39.5mm 
slot_len  12mm 
slot_wid  1.5mm 
stub_len  21mm 
Designing the Wilkinson Power Divider
The input signal power must be divided equally among 16 patch radiating elements. In other words, a 1:16 power distribution network is needed for this project. The design of a Wilkinson power divider is described in detail in EM.Picasso Tutorial Lesson 9: Designing a Microstrip Wilkinson Power Divider. An Ωshaped microstrip ring is used to create a threeport network. The input and output microstrip lines all have a width of 2.4mm with Z_{0} = 50Ω. The microstrip partial ring has a width of √2Z_{0} = 70.7Ω and serves as the two quarterwave arms of the Wilkinson power divider. It is determined that if a lumped 100Ω resistor is connected between the two output arms of this divider, better return loss and isolation levels are achieved. The figure below shows the geometry of the optimized 1:2 Wilkinson power divider.
The geometry of the Wilkinson power divider with the lumped resistor. 
Constructing a FourElement Patch SubArray
Good texas holdem hands. A binary Htree structure is used to construct a 1:4 Wilkinson power divider network as shown in the figures below. In this case, the network involves three ringtype Wilkinson power dividers.
The geometry of the fourelement slotcoupled patch subarray with a corporate feed network. 
The geometry of the fourelement slotcoupled patch subarray with the patches in the freeze state. 
The multilayer structure is parameterized with the design variables listed in the table below. Of these variables, only the open stub length needs to be changed to 18.5mm, and rest of them retain their original value for the best input impedance match.
Design Variable Name  Optimal value 

patch_len  39.5mm 
slot_len  12mm 
slot_wid  1.5mm 
stub_len  18.5mm 
resistance  100 Ohms 
The figure below shows the planar mesh of the subarray. The patch and slot elements are discretized with a mesh density of 30 cells per effective wavelength, while the corporate feed network requires a higher mesh density of 50 cells per effective wavelength due to the narrow line hosting the lumped resistors.
The hybrid planar mesh of the fourelement slotcoupled patch subarray with a corporate feed network. 
The 4element slotcoupled patch subarray is simulated using EM.Picasso's planar method of moments (MoM) solver. An adaptive frequency sweep is performed to compute the frequency response of the structure over the frequency range [2.2GHz  2.6GHz]. The figures below show the variation of the subarray's return loss with frequency and its 3D farfield radiation pattern computed at 2.4GHz.
The return loss of the 4element patch subarray over the frequency range [2.2GHz  2.6GHz]. 
3D radiation pattern of the 4element patch subarray computed at 2.4GHz. 
Constructing a 16Element Patch Array
The binary Htree structure described earlier is expanded to construct a 1:16 Wilkinson power divider network as shown in the figures below. In this case, the network involves 15 ringtype Wilkinson power dividers.
The geometry of the 16element slotcoupled patch array with a corporate feed network. 
The geometry of the 16element slotcoupled patch array with the patches in the freeze state. 
Using the same mesh densities as before, the planar mesh shown in the figure below is generated for the 16element patch array.
Slot Antenna Design
The hybrid planar mesh of the 16element slotcoupled patch array with a corporate feed network. 
The matrix size for this planar MoM simulation is N = 10,771. EM.Picasso's LU solver was used to solver the linear system. The total computation time including the LU decomposition, backsubstitution and computation of the full 3D farfield radiation pattern at an angular resolution of 1° along both the azimuth and elevation directions was 150 seconds. At the end of the planar MoM simulation, the following port characteristics are reported:
S11: 0.447781 + 0.118984j
S11(dB): 6.682387
Z11: 123.053609 + 37.286922j
Y11: 0.007443  0.002255j
The figures below show the 3D farfield radiation pattern as well as 2D Cartesian radiation pattern cuts in the principal YZ and ZX planes computed at 2.4GHz. A directivity of D_{0} = 17.3dB is predicted for this array.
3D farfield radiation pattern of the 16element patch array computed at 2.4GHz. 
The 2D Cartesian radiation pattern of the 16element patch array in the YZ principal plane. 
The 2D Cartesian radiation pattern of the 16element patch array in the ZX principal plane. 
The figures below show the surface electric current distribution maps on the patch and feed planes, as well as the surface magnetic current distribution map on the middle ground plane, all computed at 2.4GHz.
The surface electric current distribution map on the feed network plane at 2.4GHz. 
The surface electric current distribution map on the patch radiators at 2.4GHz. 
The surface magnetic current distribution map on the coupling slots at 2.4GHz. 
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