Antenna and EM Modeling with MATLAB Antenna Toolbox. Sergey N. Makarov

Чтение книги онлайн.

СКАЧАТЬ If an antenna is either an open or short circuit, what is its reflection coefficient, Γ? Hint: The problem may be solved using the currents associated with the reflected and forward waves in Eq. (1.18), but introducing a minus sign to account for the opposite orientations of the two currents: .

      4 4. Repeat Problem 3 ifa quarter wave transmission line with Z0 = Rg is added to the antenna;a full wave transmission line with Z0 = Rg is added to the antenna.

      5 5. The exact values of the antenna reflection coefficient Γ (computed vs. characteristic impedance of a 50 Ω transmission line) are0.1;0.316;−0.5.Determine the reflection coefficient values in dB.Determine antenna impedance.

      6 6. Calculate and plot to scale the phase of the reflection coefficient in Example 1.10.

      7 7. In Example 1.10, a coaxial transmission cable RG‐58 with Ζ0 = Rg = 50 Ω and with the length of 1 m is added to the antenna. How does the plot in Figure 1.8 change?

      8 8. The lower frequency of an antenna band is 2.5 GHz; the upper frequency of the band is 6 GHz. Determine the band center frequency and the antenna impedance bandwidth.

      9 9. In Example 1.10, we use a generator with Rg = 100 Ω. How does the antenna impedance bandwidth will change?

      10 10*. A thick cylindrical tubular dipole has lA = 15 cm, a = 5 mm. Using MATLAB Antenna Toolbox, determine the center frequency of the band and the impedance bandwidth percentage. How do those values relate to the values found in Example 1.10?

      11 11*. Browsing the Antenna Toolbox Classes, provide at least one example of an antenna that has a significantly larger bandwidth than a thin dipole of the same length when matched to a 50 Ω generator/transmission line. Justify your answer by numerical simulations.

      12 12*. A quantity that is also often used in analyzing the port characteristics of an antenna is return loss. What is it? How is it different from the reflection coefficient? Use the MATLAB Antenna Toolbox to plot the return loss and the reflection coefficient of a dipole antenna as described in Problem 10. Comment on the results.

      13 13*. Your boss at the startup you have joined tells you about this new antenna that has been designed and called an ESD – an electrically small dipole. Your boss claims that the spatial radiation characteristics (far‐field directivity/gain) do not change as the operating frequency is lowered. Investigate this claim by using the dipole in the MATLAB Antenna Toolbox library, modifying it as per the dimensions in Problem 10 and analyzing at the following frequencies: 200, 150, and 100 MHz. Do the following:Calculate and plot the 3D radiation pattern of the antenna at the listed frequencies and make a table of the maximum directivity reported in the plot (look at top‐left corner).Tabulate the impedance of this antenna at the listed frequencies.Comment on the results.

      14 14. Is the common household microwave oven an antenna? Justify your answer.

      Конец ознакомительного фрагмента.

      Текст предоставлен ООО «ЛитРес».

      Прочитайте эту книгу целиком, купив полную легальную версию на ЛитРес.

      Безопасно оплатить книгу можно банковской картой Visa, MasterCard, Maestro, со счета мобильного телефона, с платежного терминала, в салоне МТС или Связной, через PayPal, WebMoney, Яндекс.Деньги, QIWI Кошелек, бонусными картами или другим удобным Вам способом.

/9j/4AAQSkZJRgABAQEBLAEsAAD/7R9QUGhvdG9zaG9wIDMuMAA4QklNBAQAAAAAACscAgAAAgAA HAJQAAlud2VocmthbXAcAgUAETk3ODExMTk2OTM2OTcucGRmADhCSU0EJQAAAAAAEKnUxlgheevq nBvC0am8KXE4QklNBDoAAAAAAOUAAAAQAAAAAQAAAAAAC3ByaW50T3V0cHV0AAAABQAAAABQc3RT Ym9vbAEAAAAASW50ZWVudW0AAAAASW50ZQAAAABDbHJtAAAAD3ByaW50U2l4dGVlbkJpdGJvb2wA AAAAC3ByaW50ZXJOYW1lVEVYVAAAAAEAAAAAAA9wcmludFByb29mU2V0dXBPYmpjAAAADABQAHIA bwBvAGYAIABTAGUAdAB1AHAAAAAAAApwcm9vZlNldHVwAAAAAQAAAABCbHRuZW51bQAAAAxidWls dGluUHJvb2YAAAAJcHJvb2ZDTVlLADhCSU0EOwAAAAACLQAAABAAAAABAAAAAAAScHJpbnRPdXRw dXRPcHRpb25zAAAAFwAAAABDcHRuYm9vbAAAAAAAQ2xicmJvb2wAAAAAAFJnc01ib29sAAAAAABD cm5DYm9vbAAAAAAAQ250Q2Jvb2wAAAAAAExibHNib29sAAAAAABOZ3R2Ym9vbAAAAAAARW1sRGJv b2wAAAAAAEludHJib29sAAAAAABCY2tnT2JqYwAAAAEAAAAAAABSR0JDAAAAAwAAAABSZCAgZG91 YkBv4AAAAAAAAAAAAEdybiBkb3ViQG/gAAAAAAAAAAAAQmwgIGRvdWJAb+AAAAAAAAAAAABCcmRU VW50RiNSbHQAAAAAAAAAAAAAAABCbGQgVW50RiNSbHQAAAAAAAAAAAAAAABSc2x0VW50RiNQeGxA csAAAAAAAAAAAAp2ZWN0b3JEYXRhYm9vbAEAAAAAUGdQc2VudW0AAAAAUGdQcwAAAABQZ1BDAAAA AExlZnRVbnRGI1JsdAAAAAAAAAAAAAAAAFRvcCBVbnRGI1JsdAAAAAAAAAAAAAAAAFNjbCBVbnRG I1ByY0BZAAAAAAAAAAAAEGNyb3BXaGVuUHJpbnRpbmdib29sAAAAAA5jcm9wUmVjdEJvdHRvbWxv bmcAAAAAAAAADGNyb3BSZWN0TGVmdGxvbmcAAAAAAAAADWNyb3BSZWN0UmlnaHRsb25nAAAAAAAA AAtjcm9wUmVjdFRvcGxvbmcAAAAAA

СКАЧАТЬ