Description:Detailed Description of Example Embodiments

[0024] It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components outlined in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0025] The use of "including", "comprising" or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "a" and "an" herein do not denote a limitation of quantity, but rather denote the p resence of at least one of the referenced item. Further, the use of terms "first", "second", and "third", and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

[0026] The Invention in its several embodiments includes a logarithmic periodic antenna with a dielectric medium a, such as a printed circuit board that is inserted between a logarithmic-periodic microstrip section and a next logarithmic-periodic slot section, wherein the border of the undersize logarithmic-periodic microstrip section is in With respect to the border of the first logarithmic periodic slot antenna section and where there is an immediate distance between the outer border of the first logarithmic periodic microstrip antenna section and the border of the first logarithmic periodic slot antenna section, vertical to the second surface, limits a first impedance gap.

[0027] The invention in its several embodiments can still include an antenna with a tappered, electrically conductive supply line and a substantially same area tappered Slot supply line. The embodiments of the invention can furthermore, an arrangement of two or more logarithmic periodic Include antennas, which are fastened in the change-over phase center opposite the Frequency orientations.

[0028] According to a non-limiting exemplary embodiment of the present disclosure, FIG. 1 depicts the Basic structure of Log Periodic Antenna. Wherein A log periodic antenna (LP), also known as a log-periodic array or log-periodic aerial antenna is illustrated. It is a multi-element, directional antenna which is designed to operate over a wide band of frequencies. The lengths and spacing's of the elements of a log-periodic antenna increases logarithmically from one end to the other.

[0029] Further, A simplest structure of the edge feed Micro strip Log Periodic Dipole Array is chosen as base design. In this work, the design of a Micro strip Log Periodic Dipole Array (MLPDA) antenna for wireless communication in C band is presented and the corresponding parameter characteristics are evaluated using the HFSS simulation software (14.0).

[0030] According to a non-limiting exemplary embodiment of the present disclosure, FIG.2 depicts the Design of Log Periodic micro strip Dipole Array Antenna. The figure 2 describes the complete completely describe the geometry of MLPDA, where L1, L2…., L8 are half lengths of dipole element, W1, W2… W8 are widths of the dipole elements, S1, S2…., S8 are centre to centre spacing between dipoles, Ws is the width of strip line and K is feed length. For proper analysis of the antenna layout, micro strip dipole elements of upper layer are denoted by odd numbers 1, 3, 5, 7. . .15, while the lower layer dipole elements are denoted by even numbers 2, 4, 6…... 16. One complete dipole is formed by considering upper and lower dipole elements as one unit, which is distributed asymmetrically over the strip length.

[0031] Further, an eight element MLPDA antenna using FR4 substrate (Ɛr = 4.4 and width h = 1.6 mm) is fabricated. The structure is very close to a standard (wire) LPDA and therefore the standard strategy of LPDA design can be used, along with some modifications. The property of log periodic structured antenna is mainly determined by 3 parameters; the scale factor s, spacing factor r and number of diploes N. All the adjacent dipole elements are printed on two sides of micro strip substrate, in an alternate way and are fed with coaxial cable at the lower end. All the elements of antenna are fed by a paired micro strip to match the resistance of 50Ω.

[0032] In an embodiment, Fig 3 represents Geometry of Log Periodic Microstrip Dipole antenna Array. Wherein the following calculations are considered. The effective dielectric constant is calculated by using a relation:
∈_(eff=∈_(r+1)/2+∈_(r-1)/2×1/√(1+(10×h)/W_s )) (1)

Now, starting with the required bandwidth of (f_u-f_l)GHz, where f_u is upper cut off frequency and f_lis lower cut off frequency. The length of largest dipole can be calculated by using equation (2)
L_max=K_1 λ_max (2)
Where λ_maxthe largest effective wavelength at is the lowest operating frequencyf_l, is given as;
λ_max=∁/√(εeff×f_l ) (3)
K_1is upper truncation constant. It depends on scaling factorτ.
〖 K〗_1=1.01-0.519×τ (4)
The length of shortest dipole element can be calculated by using equation

〖 L〗_min=K_2 λ_min (5)
Where λ_min is the shortest effective wavelength at the highest operating frequencyf_u and K_2is lower truncation constant and are calculated by using equations (6) and (7)

〖〖 λ〗_min=c/√ε〗_(eff×f_u ) (6)

K_(2 )=7.08×τ^3-21.3×τ^2+21.98×τ^1-7.30 (7)
Now, to cover the desired frequency range, number of dipoles can be calculated from the equation (8)
(N=1+□log log (K_2/K_1 ) +log⁡(f_1/f_u ))/logτ (8)

The width of the dipole element can be determined by using the expression of characteristic impedance Z_0 of cylindrical dipole as given by
Z_o=η_o/π×[l_n/a_n )-2.25] (9)

Where a_n= radius of equivalent cylindrical dipole and l_n= half length. The width of printed microstrip dipole elements are calculated by using formula in Equation (10)

W_n= π×a_n (10)

After determining the length and width of the first dipole element from Eq10, other lengths, widths and spacing’s can be calculated from well-known equation of scaling factor given by Equation (11)

〖τ=L_n/L_(n+1) =W_n/W〗_(n+1)=s_n/S_(n+1) (11)
Where n= 1, 2, 3…, N. Another important geometrical parameter of MLPDA is spacing factor, σ which can be calculated by using Equation (12)

σ=S_n/(4×L_n ) (12)
By using all the design equations the specifications and dimensions of the LPMDA array are presented in table 1.

[0033] In a similar embodiment, FIG. 4 (a &b) illustrates the prototype fabricated top and bottom views. Wherein a Fabricated of Log Periodic Microstrip Dipole Array is represented pictorially.

[0034] In accordance with a non-limiting exemplary embodiment of the present subject matter, Figures 5-7 shows the Co-Polarization and Cross Polarization of the designed Log Periodic Microstrip Dipole Array antenna at different resonant frequencies namely 5.3GHz,6.2GHz and 7GHz respectively. The peak gain is more at 7GHz.

[0035] In an emboidmnet, the fabricated Log Periodic Microstrip Dipole Array is resonated at three resonant frequencies namely 5.3 GHz, 6.2GHz,&7GHz respectively.Also at 7GHz, the return loss value is obtained as -22.4119dB.The Corresponding gain is measured as 6.9dB, the VSWR value is 1.17.It is also observed that %Bandwidth is enhanced to 33.84% in comparison of the basic printed log periodic micro strip antenna[ 4].The designed antenna is very useful for C-band satellite applications like broadcasting, mobile communications and aeronautical applications.

, Claims:
We claim

1. DESIGN OF LOG PERIODIC MICROSTRIP DIPOLE ANTENNA ARRAY FOR C-BAND APPLICATIONS, comprising:
a dielectric substrate; and
fabricated using FR4 Substrate with a dielectric constant εr = 4.4 ; and
PLDPA array;

2. Wherin the device as claimed in claim 1, FR4 substrate with Ɛr = 4.4 and width h = 1.6 mm is used.

3. Wherein, structure Parameter Value are
Width of parallel strip line, WS 3mm
Feed length, K 6.5mm
Scaling factor, Ƭ 0.90
Spacing factor, σ 0.166
Effective dielectric constant, Ɛeff 3.6962
Length of largest dipole, Lmax =2L8 16.92mm
Length of smallest dipole, Lmin=2L1 8.10mm
Number of dipole elements, N 8